On the vast majority of deals I do, I either use Escrow.com, Payoneer Escrow, or the escrow provided by a domain name marketplace. The only exceptions are on deals with someone I know very well and trust explicitly. I think using an escrow service is essential, and it is a small cost.
Not only does escrow help protect funds while adding certainty to a domain transfer, but it also provides an extra tracking mechanism. Should a problem arise, the escrow service can track the funds with a court order / subpoena. In addition, the escrow services will do a verification to ensure the other party is not on the OFAC list.
In short, using escrow is a good way of securing a transaction and ensuring payment or delivery of the domain name.
I probably use an escrow service on 95% of my deals, with very few exceptions. Some people won’t transact without using escrow, and that is also smart. You can’t go wrong being overcautious. Other people are more casual and don’t use escrow. Perhaps their deals are much smaller and using escrow is more of an annoyance or is cost prohibitive. I am curious where you stand: