This.
I have an elderly aunt in one, moved there in her early 80's, now in her 90's. Lovely little flat, great social life, they were incredibly well looked after during Covid, staff made sure they all had foods, meds etc. When she had a bout of ill health they arranged ambulance, called us to let us know. She's currently away on a "little coach trip" for a midweek break with one of her new chums.
Compared to the worry of her living alone in her house the M&S place is a godsend. She can have people over for meals in her flat, or invite them to lunch in the communal dining room. The food isn't 5 star to be fair, but it's nice and she loves it.
She was able to have her little dog there with her until he died (you can't get a new one but can take your existing dog) she now dog sits for one of the other residents.
I know when people need more care then they facilitate carers coming in so that the residents can stay as long as they can in their own home.
Yes the service charges are mind boggling, around £500 a month in my aunts place, and that's after buying the flat - but she sold her house to finance the move and it really was a sensible decision for her.