I came across a version of EMT that is new to me. It's belled like PVC and has a built in compression fitting.
Were these popular at one point ? Has a code change made them obsolete ? Who made them ?
We used them for one large riser job 25 years ago and that was the last time we used them. For straight only EMT runs they might be faster and cheaper but once you involve bending elbows and offsets they are a pain to work with. We had a big pile of them on the floor from guys cutting them off. If you must use them use the set-screw version.
We used them on a project (actually one material order) once but as the others have stated, it did not work out, we still bought the same amount of couplings the estimate showed.
I have some 2 1/2” emt with the bell ends, set screw, laying around somewhere, came back from an unknown job. Probably be ok parallel long straight runs.