[Aissen]

I think only the M2 air (and M1 pro, depending on size) can use fast > 30W charge; it varies by model.

[happyopossum]

No, even the M1 air can charge at 45w, which is a good bit faster than the 30w adapter they ship with it.

[Retric]

Only for a relatively small portion of the batteries charging curve. The real advantage is when charging while turned on.