If the other player is pretty inconsequential I like it for Houston. The odds of Velasquez being as good as Giles are pretty small, and a back-end soft-tosser + non top-100 prospect is a pretty fair price for the sure thing IMO.
I dunno, maybe it wasn't obvious that he was available? You have to think a lot of teams would pay him 2-3M and would have been willing to throw some cash or a PTBNL SF's way.
Goins could be useful as a guy you send back and forth to AAA depending on the health of Travis. Carrying him and Barney while Tulo and Travis are healthy would be silly, but having both in the org would be good for depth.