Interesting. I put "middle man" in quotes because I can see it wouldn't have to be a person or group of people. I can see imagine it being a protocol. 

I totally agree that reversible transactions have tradeoffs, I mean they cause all kinds of fraud, and costs the banking / financial system much more to deal with.

So I have some experience with protocol level escrow stuff, like in lightning channels or even in Bisq, so I think there might be a way to do it without a 3rd party, but regardless adding that middle-man or escrow protocol adds additional complexity and time to complete a transaction. Just throwing out my thoughts.

Rock

That's a good one. Yeah but this is really solved by escrow services. In this situation you really need a third party "middle man". Reversible transactions have their own set of tradeoffs.

kepford

bitcoin

Does Bitcoin have any negative tradeoffs or is it just all positive?

The most obvious tradeoff in my opinion is irreversibility of transactions. I think it's a good thing overall, but scams _might_ be harder to deal with for average people.