For buyers of new devices that may be true. Yet I've sold plenty of phones I had bought second hand (after years of my own use), and those with user swappable batteries are far more likely to be reused without great expense. More so if they also have an SDcard slot to minimize wear on the soldered storage.

As phone features plateau we should strive to make them last longer and avoid unnecessarily consuming tons of new material every year. (IIRC a single iphone consumes like 0.5 tons of materials to go from the ground to the pocket.)