Earlier quoted context omitted.
Interesting part: > It is crucial for an IDE to have access to home or host filesystems, for Git repositories, and for other external uses, otherwise it is not very useful. […] They also need additional permissions to work, since making them use portals for all host system file access is technically complicated. Audacity and VLC face similar barriers, but all these applications should eventually be able to use portal…
It seems pretty obvious to me. Some programs aren't going to be very useful if you don't let them access resources on your computer, like the filesystem. Some "stateless" apps will do fine without it (Spotify), but anything designed to create and edit files you want to live outside the sandbox is going to need to access them.
I want to be able to give programs exactly access to I want it to access, and just when I want to give it that access. This way I'm sure my SSH keys (or private emails,or bitcoin wallet, etc) will never be leaked by a malicious VSCode extension.