I’m afraid this is unlikely to happen in the near future, for a number of reasons:
- The watch has a small battery, and Apple intend it to be used for brief interactions, not longer sessions.
- The screen is small, and you’ll likely give yourself sore eyes, sore arms or a sore neck if using it for more than short periods.
- Some of the technologies Anki relies on are not supported on the Apple Watch. A Watch implementation would require a significant amount of engineering work, and at the moment there are other areas that would benefit a larger number of users.
Sorry to be the bearer of bad news 