FSD (and stock Autopilot, for that matter) are systems you engage while driving, similar to Cruise Control. I feel like the capabilities are different enough that the average driver wouldn't get too used to FSD over a couple week period.
For me as someone who drives a decent amount of country backroads, I'm wondering whether the stock Autopilot obeys stop signs. I know it didn't when I first got the car, and I wasn't in a hurry to test if they added the functionality. I could see maybe someone renting a Tesla with FSD, getting used to it, then not realizing that the next Tesla they rented without FSD was going to blow through a stop sign.

Always crazy seeing a The Big Hit reference in the wild