I wouldn't do this IF other options exist. Obviously none of us knows how many years we have left to live, but since these mortgages are usually sold to elderly people, the bank is usually going to "win" with these things.
Let's talk about my grandmother, who is 96 years old and is in need of money. She owns a small, immaculate home worth about $150,000 (I know that'd be a cardboard box in some areas of the country, but here it's a small but nice, all-brick home in a good neighborhood). She does have a mortgage on this house, so a reverse mortgage probably wouldn't be an option for her. But let's pretend it is for the example: If she took out a reverse mortgage, she'd have to pay large up-front fees to the bank . . . then she'd get a "paycheck" for the rest of her life, but remember that she's 96 -- IF she lives to be 100 and received $500/month, she'd only get $24,000 . . . and then when she passes away, the bank would have her up-front fees and a house worth $150,000. They'd profit something like $130,000 for a relatively short-term investment. Obviously, some assumptions are involved in my math; it's possible that she could live to be 120 -- but the bank's guessing that she won't.
Do the senior citizens you know have families? I'll tell you what we've done, my grandmother and me: She offered ME the house, and I'm buying it from her. I'm essentially "taking up payments" on the house, and I've promised to take care of the taxes and all repairs for as long as she lives. She, in exchange, has complete use of the house -- again -- as long as she lives. When she passes away, the house will be mine to rent, sell, or use myself.
She's happy in that house, and she hopes to live there for the rest of her years. My husband and I are also making contingency plans for her to move in with us IF that should become impossible (we're looking at adding another bathroom and turning our office into a bedroom). She's also happy that the value of her house will stay with me and my children rather than going to the bank.