Smash (at least, the fine-powdered stuff) is more versatile then noodles - as a universal thickener, it is excellent for adding to soups, etc, as well as being the staple part of a meal when flavoured with tuna or lumps of decent cheese. The powder is also pretty dense compared to noodles, so takes up rather less space when packing, and in an oversized sandwich bag, can often be packed into otherwise unusable space.
Noodles do have the advantage of being easier to make a wet meal from, allowing extra hydration, but for an evening meal before a long sleep, extra hydration isn't always what the body wants, and a sticky meal can be less messy to share when a few people are sticking their spoons in while lying in their pits - reaching over a mate to try and get a spoonful of noodles in liquid can end up with more food on the floor (or friend) than in the caver.