I don't know much about macOS these days, but I was under the impression that Casks were for applications, and normal formula were for things installed in your PATH as standalone binaries. The .app needs a few extra things bundled up.

EDIT:

I looked it up, the issue is that homebrew explicitly doesn't want .app formulas: https://docs.brew.sh/Acceptable-Formulae#stuff-that-builds-a...

IDK what they expect. Every open source application developer needs to pay $99/yr now?

I mean you can always get the DMG from the releases on GitHub, so I guess we can just point people there and abandon homebrew. https://github.com/alacritty/alacritty/releases