I am not aware of any advantages other than it being easier John, but I read a lot of posts from people saying they were giving up on the marriage visa and reverting to retirement as it's too much hassle.
I have no personal experience, so it was just a suggestion.
Your situation seems very similar to mine and I must be honest I gave up on health cover and opted for accident instead.
I am in good health and take regular exercise (I run 10k and swim for 30 minutes) but I got tested for a few things to be safe before coming to Thailand. All of these are now excluded as well as a couple of things I had treatment for and given the all clear.
I could accept this if the premium reduced with everything they exclude, but it doesn't.
I think the pre existing things last for 10 years, but someone will correct me if I am wrong and it's difficult to get insurance after age 65 years.
Some people state they could not open a bank account now without an agent, others state it is still possible, so depending on where you are try them and see.
It is a year and a half since I opened my account, so things could have changed, but I still had to go to several banks and branches of banks to find one willing to open, even though I had the letter from immigration and everything.
The bank account was the most difficult part of the visa process, everything else is just filling in simple forms and providing your documents at the correct time.
we applied through the uk gov site when I did it about 4 years ago, I have no idea if they have outsourced some of the work to India now, but it is still on behalf of UK immigration if they have.
Most Thai people don't, but if you read his post his gf clearly seems to have the credentials, which is why I suggested it.