By every metric it's horrible. Searching for the term, using it as a verb and noun, ease of saying it in a sentence, recognition, as a logo, color scheme, the fact that X sounds a lot like ex as in something I previously engaged in but no longer do (irony) . I mean I could go on and on.
I refuse to believe no one told him how poor of an idea it is, I think he just has too much money to be able to listen to others.
The company redefined a word in the space of less than a decade. Huge marketing success when you pull that off. Elon just couldn't let go of his old idea from the PayPal days that the rest of the board back then told him was a bad idea.