Awful clothes? What video were you watching?
If I ever open my own dojo, periodically training in street clothes is one of my priorities. Work clothes training too. At least twice a year to account for winter clothes and summer clothes. We dress completely different in June vs January. Punching and kicking in a suit, tie, and dress shoes or a dress, skirt, etc. isn't going to be the same as barefoot in a gi. There's a good reason why LEOs wear clip-on ties vs regular ties. If you wear a traditional tie, you should know how to keep it from becoming a leash or strangulation liability in SD.
Goodwill has plenty of clothes for cheap that'll approximate pretty much anyone's work and street attire.
This video motivated to ask my CI if he's open to the idea.