Firefox has been and in some cases still is far, far worse than .2s slower, but even not considering that, the reality is that chrome has more support and thus gets more development and attention.
This results in some websites not working properly or at all on Firefox, while this isn't Firefox's fault it is a thing nevertheless
While this is not a serious post I'm going to take it seriously, so here are some of the reasons:
Nobody can easily remember the precise file name and if you don't get the first letters right you're screwed(did I mention capital letters matter?)
Wtf is --vo=tct? No sane person is remembering all of that (same goes for the rest 10000 parameters and options)
Again, waaayyy too many parameters, who remembers their playlist name? There is no autocomplete here, you're on your sad own in your sad little room with your sad little feelings, because there's no one there to tell you the song's precise name, because computers are assholes and don't hate you.
So why GUIs? Because they make computers seem like friendly fellas which actually care about you and give you options, tell you the available functions(without deciphering a 50 pages manual if done well)