It's not worth it to earn 8$ by giving your KYC
Exactly.
User is basically selling his personal documents copies for $8.
If someone wants to buy your documents copies for $8, certainly he wants to do something with that.
A few options:
-Bitwala may want to inflate their list of investors with fake clients, such as OP.
-Bitwala may be willing to sell those documents to a third party who also needs to inflate their numbers.
Even your reputation is at risk, as you don't know what a third party will do to your documents.
Everything that is on the web you can consider it exposed and leaked.