How many hours do I have to move my iPad around before measure actually starts measuring anything?

Seems like kind of a useless program, to be honest. In the time I’ve stood here moving my iPad around I could have taken the measurements with a tape measure. Is this just completely useless technology or does this program actually do something meaningful if you wave the iPad around long enough?

I know I posted this in messages but that’s only because apple apparently got sick of explaining why this app is useless so they provide no topic on measure to select when posting.