We already went through the "why buy an X whose batteries can't be replaced" when the iPhone showed up. Same reasoning: between smaller size, greater capacity, less breakage, and wanting a reason to buy the new model ~2 years hence, most are happy to replace devices over dead fixed batteries.

I'm on conference calls >4 hours daily. Wore out my AirPods series 1 set, bought a replacement series 2 (wireless charging) set a couple months ago, no question would have ordered the Pro today if not having just bought the series 2.

Compact convenience has its own value.