Hogwash. Pure unadulterated hogwash. Thousands of road musicians can not be wrong. Hardshell cases with an inch or so of padding are the best protection next to flight caes. Cardboard ones with little or no padding should be scrapped. Gig bags of quality are sufficient if the instrument never leaves the musician's hands. Even then there are risks.

My use includes both options as sometimes I only need to carry a guitar a short distance and a gigbag will do. Normally the hardshell cases are used. Any time that a guitar has to ride with anything else out of my hands, the gigbags are left at home. However, a cheap low quality gigbag should be avoided. I only use good ones with lots of padding and reinforcement and sometimes additional homemade padding around the neck if the fit is loose.

If quantity and weight are problems, a folding two wheel cart is worth its weight in gold, but costs about the same as a decent case.

Mooh.