I would love this. I often play a decades challenge and add those things to the lots I make to look like marketplaces in saves. I do often cheat the money for hiring staff for the booths, but it would be nice to not have to do that.
I'm on console so I don't use mods but my played Sims generously hire vendors when visiting a community lot with a load of empty booths. But vendors only carry on working for a few hours and then leave and I have to hire them again.
It's been a popular request over the years to just have vendors arrive automatically so I hope we see it added at some point.
