As for the gas gauge, the trick is to reset the local odometer at every fillup, and you'll have an indication of the remaining fuel. Some older cars don't even have a fuel gauge, they just have a lamp that glows when it gets low.
If you want to talk specifics, you’re supposed to be able to see your speed and how your car is performing. You should be prepared for contingencies, like your temperature changing or a yellow/red warning on the dash. You may need to deal with a problem in the car, like grabbing something that could slide under the pedals.
The same goes for farsighted driving. Yes, in most cases you could just follow traffic and you wouldn’t need to read street signs or look at traffic a mile ahead. But you need to be prepared for unexpected situations, and you’ll generally do worse just mentally managing your reduced vision.
I’ve driven without my glasses and tested an unexpectedly bad trial prescription in a car, if it matters.