Apparently there is some transit system in China that uses this format for payments. So you can get one of those cards, add it to your watch, and program the RFID system to accept the ID of the card you got. There was an HN article about it this weekend.
Don’t know about Apple Watch development, but the scope of what you can do with Garmin's SDK is limited, apps run in a VM, ie no native code with respective performance issues and, as important, their developer support is a complete and utter garbage.
It's a lucky day when someone from Garmin graces Forums with their presence and bestows few sentences they think could pass for an answer.
In other words, yeah, the SDK is free, you can side-load and it’s not hard to write for, but you just can't write much.
It's severely limited in terms of what you can do. Garmin doesn't support some Unicode (Georgian) characters, and when you get a notification with Georgian characters, watch freezes, starts heavily draining the battery and then resumes in a few seconds.
Garmin has refused to fix this for many many years, and there's no games you can play with SDK that will help you fix it yourself
Less hackable in what way? I've found it's tremendously easier to write a watch face for the Garmin than the Apple Watch. I know, I've done it (and if you, like me, don't want to share your watch face, leave it in Beta all the time).
