Things I have learnt about batteries on any consumer equipment:
1. No-one's idea of "real world scenario" seems to match mine, because I never get as many hours as salesmen or reviewers do out of new machines.
2. All claimed reports on capacity loss are wrong, and need to be cut by about a quarter unless the battery is left outside of the machine in a cool, dry environment.
3. When batteries start going wrong - e.g. bulging, leaking, etc. - you want to take them out now. Possibly even yesterday, or last week. And it's imperative to have visual clues that this'll happen, otherwise you will (at best) ruin your hardware.
4. There's always room for a spare battery. There's not always a spare power outlet and adapter.
5. Batteries are cheaper and manufactured by third parties for longer when they are easily replaceable. I can still get batteries for 6-8 year old laptops that I or my colleagues/family/friends use.
6. I take better care of my hardware than anyone else, and I am also available to me wherever and whenever I am, so battery replacements are most conveniently done by me.
7. I also take better care of my private data than anyone else, and I'm not going to waste my time removing my hard drive just so someone else can replace my battery. Even if there were a convenient audited full-disk encryption solution for OS X, it doesn't mean I'm going to ignore the principle of multiple layers of defense - where one important layer is "don't give your machine to anyone else unless unavoidable".
What's going to happen in 2-3 years' time is what happens with every other new battery tech that's ever been divined: heavy or (as yet undefined, since it depends on the tech) atypical users will find their batteries mostly dead. Light users or those who buy a new machine every month will claim correctly that it doesn't affect them.
I can just about stomach getting a low end iPod with a hard-to-replace battery. A laptop, or even a phone? For all the reasons above, never.