And just where do you plug that extension cord in at?
Usually the garage lighting is on a separate circuit from the outlets. A combination switch GFCI outlet (one of these) usually lets you add a receptacle to a lighting circuit. Granted, some older homes are missing the neutral wire in junction boxes used for switches, hence the usually. If there's a garage door opener present, that's also typically on its own dedicated circuit as well. Admittedly, though, routing a cord down from the ceiling can present its own set of challenges.
Newer homes often tend to have the breaker panel in the garage anyway, in which case it makes sense just to go whole-hog and put in a NEMA 14-50 outlet or hardwired EVSE.
You have to turn the light switch on first, and most of those are el cheapo rated for lighting only, not motors, like the things I mentioned above.
Lighting circuits are usually lightly (pun intended) loaded, especially if most of the home's bulbs have been upgraded to LED. I actually installed one of these fixtures for my brother because for whatever reason, his house actually had no exterior outlets (my guess is the siding was replaced at some point before he bought the house, and they ended up covered up). The outlet inside the fixture is a genuine UL listed decora style 15A GFCI outlet. Granted, yes, having to leave the light switch on means relying on a dusk-to-dawn sensor (which these sort of combination fixtures generally do include) or a smart bulb.
There are very few cases this should even be considered. You can't do it if you rent. Many (most?) locales will require a permit and licensed electrician to perform it.
If you rent, swapping a breaker and an outlet is an entirely reversible process when you're getting ready to move out. I certainly wouldn't recommend doing it without the landlord's permission, but chances are if they understand that it's not a permanent change, they'll probably be fine with it.
As for getting a permit, let's just say Home Depot and Lowes would have a lot less customers if every DIY handyman did everything by the book. Nothing about changing a breaker or outlet is particularly difficult, and even if someone doesn't feel confident doing it themselves, it's generally something one can make a post on social media about and get help from a friend over a pizza and some cold beers.
Again, you're in the mindset of someone who probably just came home with shiny new Tesla, Rivian, etc. I'm talking about someone who is browsing cars.com sorted by price and thinking "Man, if I could get home charging rigged up, one of these used EVs might actually work for me!" L1 charging is rather limiting for longer daily commutes and it can take over a day for some EVs to recharge at L1 speeds from a long road trip. A 6-15 outlet cuts the charging time in half.