For months, rumors have circulated that Chinese tech giant Huawei was hard at work on a homegrown operating system, an increasingly necessary step toward independence after US sanctions prompted Google to sever ties. It’s now here: HarmonyOS, or Hongmeng in China. By all appearances, it’s an interesting, innovative take on what a modern-day operating system should be. Just don’t call it an Android replacement.

HarmonyOS made its debut at Huawei’s developer conference in Dongguan, China, where Richard Yu, CEO of the company’s Consumer Business Group, talked up its wide-ranging potential. “We needed an OS that supports all scenarios, that can be used across a broad range of devices and platforms, and that can meet consumer demand for low latency and strong security,” Yu said.

It’s true that HarmonyOS has been built with that breadth of applications in mind. The open-source platform is destined for smart TVs, smartwatches, and a bevy of Internet of Things doodads. Its microkernel architecture is lightweight and, more important, free of any legacy baggage from the Linux kernel that underpins Android. (The kernel is the core of an operating system, the hands that make the marionette dance. A microkernel is just a stripped-down version, tugging one or two strings instead of 10.) Huawei touts HarmonyOS as having a “Deterministic Latency Engine,” a fancy way of saying that it can better prioritize resources when apps and functions compete over them than Android can.

“I think Huawei is under-communicating the work it will take to make this successful.” Patrick Moorhead, Moor Insights & Strategy

While smartphones weren’t the primary focus of Huawei’s announcement, they’re clearly top of mind. At a press conference following the event, Yu said that Huawei was “waiting on an update” to see what products it might be able to use Android in, given the slight thawing of geopolitical tensions in recent months. In the event that it’s still blocked, Yu said, Huawei is prepared. “If we cannot use [Android] in the future, we can immediately switch to HarmonyOS,” he said.

As you might have guessed, it’s not quite so simple.

While there’s no reason to doubt that Huawei can put HarmonyOS on a smartphone—Chinese media says it’s already in the works—the mere presence of an operating system doesn’t make a device usable, any more than the presence of a big tent guarantees a circus performance. Without apps, HarmonyOS has very little to offer. And despite Huawei announcing a billion-dollar investment in getting developers on board, those apps may be hard to come by. Developers will be able to port Android apps over to HarmonyOS, but that process may not be worth it for many.

“I think Huawei is under-communicating the work it will take to make this successful,” says Patrick Moorhead, president of Moor Insights & Strategy, a technology analyst firm. “Most every Android app writes to specific Android APIs, so any code that touches cameras, fingerprint readers, AR cameras, microphones, proximity sensors, and even privacy and security standards must be altered.”

That potentially makes HarmonyOS a tough sell, especially given that smartphones aren’t its initial focus. The exception is in Huawei’s home market of China, where the company has enough clout to attract developers. But this is a global company with global ambitions. Internationally, HarmonyOS will face the same problems that felled Windows Phone and Tizen and other aspiring Android and iOS alternatives: Without apps, no one buys the devices. If no one owns the devices, developers don’t bother tailoring apps.

There’s another layer to the question of HarmonyOS’s smartphone viability. While Huawei touts the ability to craft one app that works across multiple form factors, that same versatility can take a toll on quality.

“To run everywhere, you can’t take advantage of device-unique things,” says Michael Facemire, principal analyst at Forrester Research. “For instance, when I put an experience on a TV that also needs to work on a phone, I either have to have a massive amount of conditional logic—in essence building two separate user interfaces—or I build to the lowest common denominator, making both experiences look poor.”