Building a reputation is a must for the merchant, because that's what usually draws the customer.
And having a good reputation as a P2P trader allows you to bring in more customers, be trusted with larger trades and more volume, and have rates which are more in your favor.
There's been a case in my local board wherein the OP got ripped off that way. The taker just took the cash and left.
Why was the bitcoin not in escrow? It's pretty standard to lock the bitcoin in escrow before arranging to meet, and good P2P platforms like Bisq or LocalCryptos will facilitate this