It depends on the application. But I'd have the bipod on the weapon anyway in case I didn't have the pack or couldn't use it and like was said, sometimes the bipod just works better.
Even when I was a SAW gunner and would do what you're talking about, firing off the ruck, or despite manhandling the fucker and shoulder firing it, I still used the bipod when applicable.
As an SDM I did it all --if you can fire a weapon in that position, I did it. In that role I actually used it more as a flip down gangster grip or to press against a doorway or window or corner for stability.
Now the Elite Iron one is the only one I know of that rotates upside down so it can be used to wedge between two surfaces and basically hang the rifle between the supports. There are several instances I could have made use of this. If you can afford this bipod, it's a hard one to beat in many areas and it's made by a great guy that made two of my cans, he doesn't fuck around in the quality dept.
I like the speed of the Harris but the Atlas is tougher. LRA no longer makes 'em I heard, they were the best IMO if you could use one that big. Elite makes a fine one that's very versatile but it ain't cheap. I can't recall who makes 'em, but two new ones are out, one is like a cross between Harris and Atlas, best of both (I really like it, want one) the other is similar to the LRA, Cadex maybe? Wish I could recall the names, sorry, but someone here will for sure.