That tool needs 100x more CPU time just to figure out some filetypes than vim needs to open a file from a cold start (which presumably includes using libmagic to check the type).
If I had to wait a second just to open something during which that thing uses every resource available on my computer to the fullest, I'd probably break my keyboard. Try using that thing as a drop-in file replacement, open some folder in your favorite file manager, and watch your computer slow to a crawl as your file manager tries to figure out what thumbnails to render.
It's utterly unsuitable for "interactive" identifications.
Though, I absolutely agree with you. I think realistically it's better to do this kind of thing in a library rather than shell out to it at all. I was just trying to get an idea on how it generally compares.
Another note, I was trying to be generous to `magicka` here because when it's single file identification, it's about 160-180ms on my machine vs <1ms for `file`. I realize that's going to be quite a bit of python startup in that number, which is why I didn't go with it when pushing that benchmark up earlier. I'll probably push an update to that gist to include the single file benchmark as well.