My problem with shorts- whether road or MTB- is the restriction around the midriff. Bibs don't cause that problem.

And I wear Lycra as it does not get caught on the saddle. When I used MTB shorts on only one ride- I caught the saddle nose so many times- I was like a novice rider. Don't know the correct term for a Tombay caused by a saddle but there must be such a word---Other than &^%$£" shorts.--But that is two.