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.
If I had the option I would have chosen a smaller camera module and included an audio jack. I genuinely think they choose to not include it as a compromise, rather than to sell a cable you can get cheap elsewhere.