Development console in Firefox is lacking compared to Chrome's. Also, the whole Firefox browser is massively slower. There have been benchmarks that prove what I'm typing here, I can't give you a definite list and I see that people started jumping on the downvote hammer so I'm not inclined to defend my opinion. It's my experience, and if someone else's experience differs - I'm glad for them.

The entire local file system api, for one: https://developer.mozilla.org/en-US/docs/Web/API/File_System... , which severely neuters any tooling designed to help you do real work on your own files.

Also a massive vulnerability surface letting arbitrary websites write whatever they want to your disk.

Definitely not. You have to explicitly select a directory from a native file system UI then confirm both read and write access for each directory, across each domain, typically each session. And system directories are blocked outright with no way to override.

This attitude is why people dismiss Firefox: “well if FF doesn’t implement it, it must be bad. Other browsers surely have glaring security holes”

(Source: I implemented the file system integration for vscode.dev)