I do have a 12 Volt booster. I was forced into buying it when I had a battery problem when returning from France and could not get the battery out because the clamping bolt was corroded. (Not on a Traction, a Renault Mégane).
I have used it about twice since, when I left the headlights on on our Jimny (no warning buzzer). It is very good for testing things like lights and horns.
I am inclined to agree that, even with 6V electrics, it is not a necessity. Just make sure that you buy a decent battery and carry a starting handle.
And don’t let helpful people bump start it for you 🙁
And don’t leave the lights on.
Roger