I will continue to keep my racks dialed in at a 90 degree hot spot because it works for me. I don't have a snake room.
I think people are sometimes too quick to make changes just because a big breeder says something.
Just because something works for the barkers, doesn't mean it will work for the average Joe. I think people aren't considering a lot of the potential complications... Here are a few that the average Joe in the average house might experience...
1. Depending on a lot of different factors, the electricity required to heat a room can be WAY more then what it costs to power several large racks.
2. Depending on the kind of floor you have, Wall insulation, and ceiling insulation you could experience huge differences in temperature from tub to tub depending on the hight of each tub. My house for example has a floor crawl space with wood floors. The floor temp is easily 10 degrees lower then the ceiling.
3. depending on the room size and dimensions and the temperature of the rest of the house, and the size and type of the heater used you could experience huge differences in temperature from tub to tub depending on distance from the heater. for example if one tub is 5 feet away from heater and another is 10 feet away... They will both have different temperatures of probably at least a few degrees.
4. Sure 2 and 3 could possibly be addressed to a certain extent using fans to circulate the air but then you are spending even more electricity! And that would make the heater work even harder.
Obviously it can be done, and some do it... But I think it is not practical for the average Joe.