A torrent client is data agnostic. It can be used to transfer any type of data over the internet.

Yuzu is designed to play specific software which is quite difficult to acquire by legal means. Very little effort appears to have been spent on improving the UX of the legal process.

(It is true that Yuzu can also play homebrew software. I think the situation would be different if Yuzu was tested exclusively on Homebrew, and only emulated features which homebrew software uses. But then no one would care about Yuzu. Yuzu has tons of game-specific fixes for commercial titles.)