Thad Starner, a Georgia Tech professor and a pioneer in wearable tech, was speaking to a big crowd at SXSW about the inspirational uses of wearable tech. He has seen it used to guide firemen in emergency-rescue situations, help a hearing-impaired person have a coherent conversation, or even give those with motor skill disabilities an option to communicate through brain signals.

Then he got a text from his wife on the Google Glass headset he was wearing. Starner has been the technical lead on Google Glass since 2010, and still wears the device. He cheerfully let the audience know he was just interrupted; one time, he said, someone messaged him during a presentation that his mic was cutting out and he was able to signal that he needed new batteries. But the moment was a reminder of the oddity that is Google Glass: a wearable that was less successful at boosting our supposed superhuman capabilities than it was at butting right up against human comfort levels with face computers. (It was also, not surprisingly, the only pair of Google Glass I saw at SXSW 2017.)

If there’s anything to be said about the wearable tech shown off at SXSW this year, it’s that it falls into one of two categories: it either performs a highly specialized function, or it’s easy to wear. To hear it at the conference, the future of wearable tech is still brighter than ever. It goes well beyond step counting and awkward face messaging, and will teach us how to play piano, as Starner later demonstrated; detect neurodegenerative diseases; or make our thoughts visible through brain-reading caps.

But it’s also increasingly clear that wearables have to offer this kind of value in order to justify their existence. And if not, they have to exist not as a wearable, but as a disappearable.

Wearables either have to be really useful, or they have to disappear entirely

Mary Lou Jepsen’s Openwater project is one example of wearable tech that's so technically ambitious that its ultimate form might not matter as much. Jepsen, a display technology expert and inventor who co-founded One Laptop Per Child and has worked at Google X and Facebook, among others, talked at length this week about her efforts to use LCD technology to read brain activity. “I’m putting screens on the inside of a ski hat to read your mind,” Jepsen told me and Recode’s Kara Swisher during an hour-long interview at SXSW. “We can look at oxygen flow really easily, because it’s LCD’s illuminated by invisible light, infrared light — the type of light you can see with night vision goggles,” she said.

However, Openwater isn’t just trying to create visual representations of what you’re thinking (which introduces a whole new set of ethical implications). Jepsen says the wearable displays can be used to flag health issues as well, such as neurodegenerative diseases or mental illness. “You could put it in a T-shirt, or even a bra, to see if you’ve got breast cancer,” she claimed. It’s a still-unproven effort, one that Jepsen has been exploring since she had a brain tumor removed in 2013, but an advanced-imaging ski cap sounds a lot more promising than, say, this clunky Sony wristband that lets you manipulative music through dance moves.

On the opposite end of the spectrum is something like Levi’s “smart” denim jacket, made in partnership with Google’s Project Jacquard. The $350 jacket, which ships in the fall, is made with conductive fibers that turn the sleeve of the jacket into a touch-responsive surface. Instead of attaching an unwieldy plastic box to the jacket, the jacket’s creators have embedded wireless sensors in a cufflink.

The idea is that you can tap your jacket sleeve to send commands to your smartphone, which is not too far off from tapping a smartwatch to send commands to your smartphone, but perhaps an easier gesture. This kind of interface — removing the display entirely and building it directly into your clothes or skin — has been proposed before; MIT’s Media Lab is even working on a smart tattoo, called DuoSkin, that would perform similar functions. Often times these interfaces are not as technically ambitious as advanced health sensors, or make any kind of lifesaving claims, but they’re meant to show the possibilities of intuitive interaction.

I didn’t have the chance to try out the Project Jacquard jacket at SXSW, but The Verge’s Nick Statt tried it on and subsequently made a good point: while it doesn’t “profess to have a groundbreaking impact on your health or well-being,” it’s still a piece of clothing a person could wear almost every day. Even if the jacket’s battery dies, or if you find yourself not using its smart sleeve all that often, you might still wear it. It’s a jacket; it’s not an obtrusive wearable that you’re trying to unnaturally jam into your everyday tech life while hoping it lives up to its wearable promises.

“You don’t really think about your eyeglasses. You see through them. It’s fluid,” Starner said at one point during his SXSW presentation. “So can we actually make wearable computers that are more like eyeglasses than binoculars?”

Starner’s question, which may have been at least partly hypothetical since he was wearing a product more akin to glasses than binoculars, is the question lots of wearable makers are grappling with: can we make a wearable that doesn’t feel like a wearable? It’s the holy grail of wearables, it seems. And if the answer is no, it better do something pretty spectacular.