Easiest to illustrate this with an example. Say I have an electric guitar chord that is about one bar long, but starts just before the bar because the strum is slow, so it's at say 3.04.04.62. I want to copy that same event to bar 11, but I want the relative position (i.e. just before the downbeat) to be preserved. If I alt+drag with snap on, it only lands on the barline. If I alt+drag with snap off, it can go anywhere.
I used Logic previously and it was intelligent enough to know that if an event was offset ever so slightly in this way, when I copied it to a different part of the song, I would want that little offset to be preserved. Studio One alas isn't :( though in many other ways it's way better of course!
Would be great to have this included, possibly as an option to select re snap behaviour if some users don't want it to do this all the time.