Practice (as opposed to rehearsal) was one of the bones of contention of my former band. It's my former band because it wasn't fun anymore so I (the founder) quit.

Anyway, here's where I'm going with this one: Practice is for the woodshed. Practice is what you do when you have room to screw up. By yourself. Practice is for making mistakes, then polishing them into something fine to hear. Recording is great for practice, because it give you the opportunity to review your errors.

Rehearsal, on the other hand, is for perfecting your "dance moves" - for learning the starts, stops, changes and finishes - of the songs, and of the set. Seemed like the guys in the band wanted to learn the songs in rehearsal, which left no time for rehearsing the dance moves.

Recording is even better for rehearsals - it helps you to differentiate whether it was the drummer or bass player (or you) that screwed up that last chorus.

Practice at home in the woodshed,
Improvise at jams,
Rehearse in the rehearsal studio.