I never use Offset Mode. I can see it being useful, but the major problem I have is that it is not evident that it has been used. You can use it on a track and subsequently forget about it and get confused about why the levels don't look right.
 
But I would like to use it. If Offset Mode could be applied per-track rather than for the entire project and some sort of flag was displayed for that track to indicate that the OM settings had been changed, then it would be a useful feature instead of a confusing one.