@NeverDie I watched a vlog (unfortunately in Swedish) about it about a week ago. The owner had used it for two months without charging it and was very enthusiastic about it. He said he used it for getting notifications, so he must be using the bluetooth feature.
Dave does have a point though that swapping the battery every 2-3 years isn't that cumbersome.
On the other hand, the charging capabilities of the Toyota Prius might have been considered a gimmick when it was introduced in 1997, and today we have electric cars with fairly long range. Technology gets better, and must start somewhere.