The question then becomes: Why do manufacturers market lights with built in batteries, when they know that a segment of the flashlight world will be alienated by that?

Is it a marketing or technical reason? The masses who want to charge in-light, without having to handle the battery? Or maybe to have less electrical resistance at the battery contact points? Or a combination of these two reasons?

Maybe they can offer the product both ways, similar to how the Smith and Wesson Shield is available both with or without thumb safety.