ATMs are fine for withdrawals, but for deposits they’re too risky. If an in person deposit goes awry the bank has a paper trail they trust to work with it, they officially don’t trust their own ATMs, so if they lose the check semi-officially assume the machine got spoofed and the check never actually existed. Much like with human tellers chances are nothing will happen, but if it you want it to happen where the bank assumes they made the mistake, not you.
I've been depositing payments from my customers to my business account, via ATMs, for two decades, and never once had a problem.
Funny enough, the one and only time I ever had a kerfuffle with a deposit, was when I walked it into the bank. Go figure.