I never said that English always used that. It's not like I could possibly know that. What I said is that using uptalk to denote uncertainty in a statement or emphasize something is a question adds expressivity to the language. How does saying everything with uptalk add expressivity? It just takes it away.
In your limited experience with language, yes.
English is an ever evolving language that isn't limited to a single geographic temporal causality, thankfully. English in 50 years, because of it's extremely wide dispersion and extremely wide cultural background, is absolutely 100% going to be different from the English you learned when you were a kid.
It's entirely possible that in 50 years people will be asking why uptalk was used to denote questions when the context of the speech was all that was needed. Hell, in 50 years Youth Colloquial English will probably be completely unrecognizable to you as it moves from a minority dialect into a majority spoken language.
What I'm saying is that you, personally, may not understand the value of uptalk but that will not stop uptalk from taking root so you might as well teach yourself to accept it.
Edit
Or just be an old man yelling at a cloud, either or.