I think it's way less of an issue for a bearded dragon since they do best with air-flow anyway...hot & dry enclosures with screen ventilation are going to circulate air
really well, and they'd be a fire hazard before anything else if closed in. Good idea to re-purpose some wood furniture for reptiles...I've done several times in the past.
FYI, you want to use only real & solid wood furniture, & thrift stores often have large entertainment centers (some real wood) for sale cheap too as so many people have
moved away from using them...at least around here, I see them all the time and priced to move.