Nail on the head. As long as you do "due diligence" and go in with your eyes open, then they basically do what they say on the tin. The idea of being free from the "Life admin" of house/garden maintenance, home repairs, etc is worth it for me, not just for the cost but also not having the hassle of having to deal with tradesmen etc.
(Though I must say I do quite like the idea of "living" in hotels as mentioned by a PP, instead of a flat so I could have some meals made for me, laundry and cleaning done for me etc.) I had pondered living on cruise ships, but I suppose living in hotels is an alternative.
But ultimately, the proceeds of my house and savings would eventually run out leaving nothing for our son to inherit, whereas with a McCarthy & Stone at least there'll be something, even if the flat makes a loss on sale, unless I ended up in a care home for a long period.
With both my parent's house and OH's parent's house, yes, we inherited their homes in full, but they'd depreciated in value over the last few years because our respective parent's lost the ability to look after them, maintain them, clean them, etc., couldn't organise their own tradesmen and we were too stressed dealing with dementia and other illnesses to do it for them, so eventually sold at undervalue because of the extent of work needed. So even staying in your own home doesn't guarantee the house remains an appreciating asset!