If you close the BofA app after you are done, you have to log in again with either password or biometrics. If you don't and just go to the home screen, it stays logged in.
It might leave you logged in for a short period of time (in case you are planning to back to the app), but it logs you out relatively quickly even if you do not “close” the app.
In that case I’d argue the issue here is terrible security in BofA’s mobile app, not the kind of money transfer.
This seems like a remarkable oversite on BofA's part. I'm with a comparitively tiny US credit union, and even their app demands a pin code to return to it if I switch to another app mid-session.