That would be wrong -- as the name suggests, W derives from U, similarly to how G, J, R, and U derive from C, I, P, and V. But it shouldn't be hard to see the intuition behind the idea that s is a "natural" letter and š is an unnatural modification.

It's almost like a lot of languages have a shared ancestry. Differences may be unusual to you. Are ș, î, or ț unusual because they don't exist in English? Those phonemes aren't common in English which is why we don't have distinctions for them, but they're important in Romanian. Not unusual at all if you're Romanian.

By your logic, 대한민국 characters are weird and unusual also, and so on...