exp. with Foundry recently, and it's cool, but I'm a bit confused as to why testing in Solidity is preferred when it's highly likely interactions w/ your contract will need to use JS/TS anyway.

3P apps call your contract directly via frontend or they have a contract that calls your contract that itself uses a frontend

/bettik founder /outercorps stalwart | ex-binance, ex-celsiusX

wouldn't it be more helpful to everyone to just test in JS/TS so implementation in a frontend is just copy/paste for much of the code?

what am I missing?

Mainly, I think foundry is more about speed of the tests themselves and the "state manipulation" power it provides. ( Say setting the chain exactly as it was during an attack or something like that. 
JS/TS are pretty convenient tho. Had to learn that specially for testing. Then came foundry. I don't wanna switch tbh xD