not sure why they did that, but nowadays it's common knowledge that you're not allowed to open a bank account while on a tourist visa, which the DTV still is.
So why even bother trying it instead of just enjoy the tike you're allowed to stay there.
Some people still try to do multiple border runs, while they know now that its risky. But they shouldn't complain if they are denied entry.
Why even try to open a Thai bank account? You already knew it wasn’t allowed. And even if 1 branche approved it, that would only last until a new manager comes in and freezes your account
I would recommend just going with the reputable companies like Safetywings. That way, you'll know it will be good in case of emergencies. I've never had issues with them and had to do 2 claims so far.