To me saying learn C++ to appreciate Rust sounds like advising someone to bang their head against the wall first because when they stop it will feel good.
Heh, there's a grain of truth to that. I think the metaphor I'd use is to try building a table or felling and trimming a tree using hand tools before getting out the power gear. Some people do like the manual approach, sometimes it's even the right choice, but generally letting the tools do the work is the better idea.
