Late last year, I wrote about how convenience was the Apple Watch's killer feature. I broke it down into five areas where I felt the Apple Watch could really save everyone time and effort by better surfacing brief but important interactions — communications, information, remote control, health and fitness, and authentication (Apple Pay).

While taken together, those five areas are absolutely killer. But other potential customers could easily find each area on its own incredibly compelling. It's a multi-faceted opportunity for Apple, and one that could make the watch appealing well beyond many expectations.

For Apple Payers and music lovers

For iPhone 5 and iPhone 5s owners, the Apple Watch gives you access to in-store Apple Pay, letting you tap-to-pay for purchases at thousands of retail locations. For walkers or joggers who don't want to bring their iPhone — or wallet — with them when they're out, it can be a great solution until you upgrade to an iPhone 6, iPhone 6 Plus, or future iPhone. So can having music with you, iPod shuffle- or iPod nano-style. It's not everything, but it's everything you really need.

For health enthusiasts

The same goes for step- and stair-counting, and other quantified life statistics. Some of us use dedicated bands for this, just like we used to use dedicated personal digital assistants like the Palm Pilot before the rise of smartphones. I've heard from friends who plan to buy the stainless steel or even gold Apple Watch also tell me they plan to get an Apple Watch Sport as well — just for exercise. That might sound excessive, but it also shows the appeal of the Apple Watch as a pure fitness device. It'll have all the right sensors and an Apple interface on top of them. That'll make for a phenomenal fitness experience all on its own.

For home automators

As home automation continues to take off, especially Apple's HomeKit, those of us who have implemented lighting, sound, temperature control, and security will need a unified and coherent way to monitor and control it. The iPhone and iPad will be great for setup and fine-tuning, but for moment-to-moment actions — turning things on and off, raising and lowering them, closing and opening them — the watch will be better. Especially when you factor in Siri. I can't wait to say "Game time" and have the lights go red, the TV switch over, and the bass come to life. Or "crash the compound," and everything have everything shut down for the night. It's one step closer to JARVIS.

For the always alert

If you're obsessed with notifications — if every time your iPhone beeps or buzzes your dive for your pocket or purse or race across the room — the Apple Watch should eliminate a tremendous amount of overhead. It'll tap you when something comes in, give you the gist when you turn your wrist upwards, and expand the details if and when you want them. Likewise, if you're waiting for a delivery, or to board a plane, or want to know what the weather is, or how long it will be before your Uber arrives, or anything else that had you pulling down widgets in Notification Center every few minutes to make sure you have the latest information, glances will give you all of that on your wrist as well.

For communicators

For those of you who simply want to be able to answer phone calls or return messages without having to pull a phone from your pocket or dash for your purse or charger, the Apple Watch will you do all of that right from your wrist. It's the same for Twitter and Facebook and potentially any other messaging system that hooks into iOS. For longer chats, Handoff will let you go back to your iPhone and its much bigger screen. For quick chats, however, and for sketches and heartbeats, the Apple Watch will be like something out of Dick Tracey.

Different strokes

Some people might just want Apple Pay. Others might prefer step-counting or the heart-rate monitor. Still others may want the Apple TV and home control, or notifications, or the ability to stay in touch without having to reach for a phone. Each one of those things could be valuable enough to make the Apple Watch well worth it. Several or all of them, in combination, could be invaluable. Never mind all the Apple Watch apps that are coming as well.

It's a product that will appeal to different people in different ways, much like the iPhone has done so. And it's a product that could come to be just as important.

Everyone I've spoken to who has used an Apple Watch for any length of time — and Tim Cook's public statements — make it sound like the watch quickly becomes so integral to their digital experience that they never want to take it off. I only got to try it for a few minutes back in September, but that was my impression as well. I can't wait to see what more than a few minutes.