I can't speak for the fish shell project - from my pov, Swift is technically a marketing tool Apple uses to keep developers focused on their platforms. It's a l

I can't speak for the fish shell project - from my pov, Swift is technically a marketing tool Apple uses to keep developers focused on their platforms. It's a lock-in thing. Indie developers love to post about it because it gives them engagement but Apple has a poor track record with open-source projects. I wouldn't reach for Swift for anything important.