Disguises are a very core part of Class-D gameplay. Though they don’t serve the greatest purpose, as most disguises are easily able to be seen through, they’re good for being what their name implies - disguises.
A small tweak I want to suggest to potentially make disguises even better would be to allow them to retain their security class tag when shooting a silenced weapon. This would allow Class-Ds with accessed to silence weaponry to remain blended in while still having a backup firearm at their ready incase things got messy. Plus, it would allow for more stealth missions Hitman 3 style, so that’s a plus.