if they did close an account they would give your money back, they wouldn't hold onto it. Once you have an account open, at least historically, they don't tend to close them, even if rules for new accounts change. Plenty of people still with accounts they opened on tourist entries when that was easy, ten years ago. This thing, for now just with Russians, is different in this regard.
I don't think it's "written somewhere" but the actual experience of people trying to open accounts on DTV is that it's next to impossible. They are being treated differently to other long term visas.
Elite is a 5 year visa just like DTV is, and both are tourist visas. I know they assist with bank accounts but regular tourist tourists used have no issues opening bank accounts either. Just saying they are the same class of visa.
DTV is also a tourist visa. There were no changes made to work permit regulations for the DTV, and it also comes stamped "Employment Prohibited". The legislation establishing DTV even says if the recipient wants to "work in Thailand" they need to change visa type. All this indicates they don't consider remote work "work in Thailand".
As Carl says this is Supplemental Security Income. You need to be resident in the US to get this, and you can't leave for longer than a month.
"is not absent from the 50 States, the District of Columbia, or the Northern Mariana Islands for a full calendar month or for 30 consecutive days or more;"
I looked up a few things and they were all cheaper here, by a factor of as much as 10x. These were cheap meds that aren't going to break the bank from GoodRx either, but it was like $0.50-$1/tablet vs $1 for a strip of 10 here. What is expensive here is branded stuff that isn't available in generic.