I understand that, and think you are correct for online purchases. In fact I ran into that myself while searching for gunpowder purchases online. Most of them wanted payment using Zelle, or some other peer to peer mechanism. None of the suppliers said "In Stock", and most of them said "Special Order".
In which case I did NOT go through with the purchase.
When putting that question to the knowledgeable people on this board, they reinforced the fact that a purchase through Zelle is like handing a person cash. If you don't know them, it's not advisable.
There are two things that I don't understand though.
1) When you are the receiver of the cash, (the above possible scams accepted) why would it make a difference? As others have said, once it hits your account, you are clear.
2) I also bank with Chase, and the option to send cash using Zelle is right there on their website. Why would they use it if it was that bad?