biggest problems I can see with that are:
1) you need the temp at or under the substrate, the box measures ambient air temp
2) cleaning the box when it gets dirty
3) potential of electric shock to the snake
4) the snake bumping it and changing the temp setting
If you don't see those as being a problem (ie, you have a solution) and you have the thermostat laying around, I'd say try it for a few hours, using a remote thermometer to keep an eye on the temps and if it isn't working then take it out.