Since we're throwing opinions around right now, here's my own:
Temp guns are not overkill.
This is a tool that is best used with anyone using flex watt and plastic tubs.
This tool will give you an accurate reading of the temps.
An Acurite unit is not overly accurate.
You need an accurate reading so that you do not burn your snake or burn your tub.
A lot of places that sell rack systems state that all warranties, etc., are void unless you measure temps with a temp gun.
Lots of people don't use them. Lots of people do.
The people who do use them will more likely than not never have a burned snake and will never have a snake that is too cold.
The same probability does not exist with keepers who don't use them.