Definitely a growing trend in the United States but still a relatively obscure term.
As a domain I am not sure it has much value.
As a developed website, I see a great amount of value simply from having it searched and the opportunity to educate people. This equates, in my opinion, to become a very worthwhile opportunity for a steady revenue stream from signing up with banks and lenders who offer an affiliate program to post ads on your site. Also look for banks and lenders that offer this type of financing and feature them as your affilitates. And definitely look into the AARP to see if they have an affiliate program as reverse mortgages are being pushed very heavily to the aging population in the USA.
Explore the possibilities of developing this domain.