The bit one can be used as a small driver in very confined spaces as well as once something is loose or to tighten up. The square drive ones can kind of be use the same way. I like the bit function best on these. For the sockets I prefer the Snap-on spinners, the FRS 40 (3/8) Also comes in 1/4 (TRS 40) and 1/2 SRS 40).
There are a couple variations so there's the ?RS 40, 40A and 40B.