Well, frankly, I'd rather have gas and air at a homebirth than people brewing up combinations of cohoshes and compressing my perineum. IMO/E, it's actually safer than some of the non-pharmaceutical things that I've seen posters say their midwives have recommended during my 3 years on the board.
To clarify; gas and air comes in a canister with a mouthpiece, which is disposable and replaced for each person using the canister. The mother holds the mouthpiece and inhales the gas and air as and when she needs the help. It does have a significant placebo effect which can help with transition, it is mood-altering and yes, if you overdo it then it can feel like a seriously "bad trip". I know this, because I used it with my first two labours and with DS1, I OD'ed on it. In retrospect, that was probably transition, though
BUT if you're looking at a choice between transferring for pain meds or gritting your teeth and bearing it, then gas and air could have kept you going over that unbearable contraction and kept you at home
FWIW, I also had pethidine for DD1's birth, as crossing the placenta wasn't an issue at that point in time, and there is no comparison between the two in terms of effects on memory. The pethidine numbed me, mind, body and soul, and took away some of the horror of what was happening. The gas and air made me feel sick, woozy and a bit disorientated. It's not comparable.
Something else to look into is the use of TENS machines, OP. They're far more common over here, and can really, really help.