Allowing basement floor to breathe
Honestly if you have a contractor talking about basement flooring in a basement were there is a fear of moisture I would fire him on the spot if he mentioned installing real wood floors.  Even in a basement with no "water" problems the humidity levels can reek havoc on wood and warp it.  I see a bad wood install in a basement a couple times a year.  I can't tell you the last time I saw a good wood install in a basement.

XPS and plywood can work in a lot of cases.  However most of the time we carpet over this type of install.  For real vinyl click lock - the good kind that is thick and pure rubber... we slap this right down on the concrete with no barrier per manufacturers instructions.  If you give me a link to the flooring you are getting I can get more specific.