With completely wireless earbuds, the rule is: when the battery fails, they have to be disposed of. Not so with the Fairbuds, that allow you to replace batteries in just a few seconds. Combined with a repairable design, the earbuds should therefore have an extremely long lifetime.
The adapter is still the inconvenience for me, just because the other option is a (tiny) inconvenience for you doesn’t change the fact that the adapter is an inconvenience for me.