AS a piping engineer
I can tell you there is no easy answer.
Stainless steel we can use for most things except chlorine and sea water
It's really good because if it doesn't corrode you don't have to allow for 3mm of material loss inside and outside for it to do it's job for at least twenty years.
Copper has the same properties but costs too much but is easily jointed so it's good for small bore stuff like house heating
. Also kills sea life so protects boat bottoms from marine
Aluminium is a real hassle. Prone to attack from too many things. Not very strong, and if you make it stronger and harder with additives it's prone to cracking.
Wood is great. Surprisingly. Not much good for pipes because the strength is in the wrong direction, but take a length of timber and wrap it in GRP. STRONG. Resillient. Easy to repair and to make. And corrosion
resistant. But a bit heavy.
There isn't a right choice, just more important parameters, weight or strength or prettiness.