I don't know anything about Chrome extensions but I know that typical bookmarklets function in all browsers. So my question is: why? Why not just using bookmarklet as is?
Naive guess—Chrome extensions run automatically on specific domains. Bookmarklets run only when clicked.
Some people hate having a bookmarks bar visible or just want to make more space for other things.
You can also get extra exposure through the chrome web store. It's not a lot, but every bit matters.
I've always been annoyed in Firefox and now apparently Chrome that you cannot just have a simple, single-file extension if you don't need any external files.
Why can't it just regex the manifest, etc. from the extension header in a comment field.
Does something like this exist for Safari or Firefox?