I have not had the same, but something pretty similar, from Neteller.
They didn't want forms, but they did want statements.
A couple of questions were utterly ridiculous, like asking me what I used my Neteller account for and with which merchants. This of course implies they accept any old merchant, and do not do any due diligence on who they accept, hence they need customers to tell them that when a transaction of -£200 goes out to the merchant "
32Red" or +£4000 comes in from merchant "32Red" the Monday following the completion of the £20 Tournament, they need me to tell them what line of business "32Red" is in.
Not only was it utterly ridiculous, but I sent them the answer THREE TIMES, yet each time they emailed back saying they hadn't heard from me. Strange, because they DID receive all the other emails for this exercise, including the one containing my ID document. They also received the email where I told them they should be able to answer two of the questions simply from looking at my account record.
The final question WAS pretty much a "source of wealth" one, and my answer was that I withdraw to my bank when I am doing so well that my Neteller balance gets higher than I am likely to need, and fund my Neteller in bad times from the money that I earlier withdrew in better times.
They were happy with this, and never did manage to receive my answers to the middle two questions, and eventually they said they didn't need to pursue the matter, and they considered me properly verified, at least until the next time.
Both Skrill and Neteller are now the same company, and they are in the line of business of providing a wallet solution for online gamblers, so it should not be necessary for them to ask what payments and receipts are for so long as the player is using the service for gambling, and this is something they can determine from the merchants involved in the transactions.
It's P2P payments that are wide open to abuse, and where they would need to ask these kinds of questions, but as I don't do P2P, the questions are pointless.
They are likely to lose customers over this, because the average person does NOT get asked this kind of thing in everyday life by their bank for their everyday transactions. It is something people might have to deal with when making very large transactions, such as paying cash for a house purchase, but normally a solicitor would be involved, and they would deal with it.
When I had those big wins a few years ago, my bank account suddenly had something of the order of £40K arrive in a relatively short period of time. Now whilst I did receive a letter from the bank asking me to come in, it wasn't to do with any questions about where I had got this money from, it was a sales pitch to grab some of it for themselves by selling me their own investment products. They probably SHOULD have asked me where this money had come from, because all they would have seen was a transfer from Neteller's own bank, which would have told them the money had come from my Neteller account, but nothing about how it got there.
Despite all this and "F&*^%$* Skrill", casinos still say they don't trust these two wallets because they are a "hotbed of player fraud", yet they seem far more anal than the banks and card providers when it comes to questions like source of wealth and what the transactions made are about. Of course, this may be in response to the casinos freezing wallet users out of all promotions, and even out of the casino completely. Neteller may have woken up to the fact that casinos are pushing their customers to a competing service, bank cards, and think they need to be seen to be doing something robust to counter the "hotbed of fraud" impression held by casinos so that they stop pushing players towards bank cards.