simply to keep the bank up to date with my address in case they decide to post something to me. I can't remember if the documents they produce for immigration show you live in the province.
It definitely seems to be getting more difficult than it was when I arrived less than 2 years ago, but back then, with a bit of persistence and travelling around banks/branches, I managed to open an account with a tourist visa.
If you try and cannot the going rate for an agent for this task seems to be 4-5,000 and might be worth doing. The rest of the visa process is easy, so agent not required (I think you know this already).
I did something like that as well as my very basic hand drawn map and he didn't even look at the Google map, just took my hand drawn one. It's a strange requirement as surely a Google map is better.
I agree, this seems to have changed in the past couple of years, but a one off payment to an agent to open a bank account (3 to 5,000 Baht) is nothing like paying an agent 35,000 Baht to get a visa and then being forced to use them every subsequent year or lose the visa.