Curry leaves are just the aromatic leaves of a bush like plant used primarily in south Indian cooking much like basil in Italian or makrut lime leaves in Thai cuisine.
Curry pastes and powders are mixtures of spices: turmeric, cumin, coriander, fennel, mustard seeds, asafoetida, black pepper, cloves etc. Every region and family has their own blend of spices.
https://www.seriouseats.com/what-is-tadka-tarka-chaunk-chhon...
Reminds me of buying "chili powder" from an Asian grocery and getting powdered chiles instead. The resulting pot of chili was very bland and way too hot at the same time.
Over here it's always just chillis.
I can imagine it being different outside the US, but this store was in Seattle so you can see my confusion.
https://en.m.wikipedia.org/wiki/Curry_tree
see the section Distribution and habitat.