The end user experience is what matters at the end of the day.
But as a backend developer, my worry is not to break the separation of concerns principle. I have provided a payment gateway, and all that a payment gateway does is execute payments. A payment gateway does not do anything else.
If you believe that the user experience of WCMp is not good enough, then that is an issue with that particular plugin. Why do you feel that an email should be sent only when the payment is done via a cryptocurrency, and not when it is done via, say, PayPal?
I would recommend that instead you enable admin approval for withdrawals (enabled by default). Then you can have a final say when one of your vendors requests to withdraw funds.
Hope this helps.
with regards