It took me a little while to figure out the question, I suppose he's referring to the roto-head type ratchet as being the swivel ratchet.
ToolGlutton, you can use a swivel ratchet as a ratcheting screwdriver with a socket bit, but other than that, I don't see the advantage of it over a flex-head.
The only times I've ever needed something other than my Cornwell roto-head was due to clearance. Sometimes (but rarely!) the head is just too wide and I have to grab a straight ratchet.
Not yet encountered a situation where a straight doesn't reach and a roto-head is too wide but a flec will work!