I didn't see any issues by using LV cable. I also found one mention of it by Roger Russell ( former McIntosh R&D ) at this website:
http://www.roger-russell.com/wire/wire.htm#wiretable

Also of interest is Russell's mention of Home Depot 'speaker wire' which oxidized after 6 months.

I tried to find the cable's voltage rating to see if it would be NEC or NFPA -approved for in-wall installation, but I could not find it. I suspect it's rated for 150 volts at best, even with it's relatively large dialectric (insulation).

In the meantime, I found what would appear to be a better alternative at Amazon with their 'Metra' wire offerings. 2x50' of 10 gauge was about $30.00 with free shipping. 12 gauge was a few dollars more.