What’s the importance for materials and patterns?

So I’m looking to get into sewing specifically for pants (it’s a pain to find my size) and I’m trying to find pants patterns. I’ve seen some for jeans or tech wear and I’m more so just wondering the important of the material for those patterns. If I used like a cotton (not ideal for pants im sure) on the tech wear pattern would it not work as well cause it’s not a nylon material?