Colours are useful: 
- to find yourself
- to find someone new 
(I'm pippelina. Pink pippelina 😎)
- for imposter detection services
(If pfp, bio, last digits of npub, color, ... match with an earlier created profile) 

 creation date for npubs can be faked as well, unless they are using Open timestamp or something like that.

And even if they couldn't be faked, they don't mean shit, because I can create Apple npub