[HereInTheHeartland]

“DEPOSIT MONEY INTO ANYONE’S ACCOUNT UNLESS YOU ARE A WELLS FARGO ACCOUNT HOLDER, OR, HAVE WRITTEN PERMISSION FROM THE ACCOUNT HOLDER.”

Those rules would likely be an attempt to prevent money laundering or some other illegal activity.
Plus why wouldn’t you write a check so you have record of what you are paying?
What stops the owner saying that you never paid them anything?

[VA40]

Because if you deposit a check to your spouses account with the same bank they put a hold on the funds. Sometimes you want to deposit cash for a spouse or a dependent.

Or maybe just because you friggin' WANT to do what you want with your own damn money.

[FrankR]

The “owner” is my son. A check takes process time, cash is an instant deposit. He lives out of town, I would have to send it to him, he’d have to take it to his bank, etc. He travels a lot for work, and this was just the easiest and fastest way to get it done.