Your opinion of a name is coloured by your age and experience.
I can see, objectively, why the name [name_f]Crystal[/name_f] would be attractive - it sounds nice and is in the same league as [name_f]Coral[/name_f], [name_f]Pearl[/name_f] etc
However the name became v popular in the 80’s after a character ( [name_f]Krystal[/name_f] Carrington) in a soap opera.
[name_m]Hence[/name_m] it became a trashy enough name. Akin to naming a child [name_f]Sue[/name_f]-[name_f]Ellen[/name_f] (character from [name_u]Dallas[/name_u])
I used to love the name [name_f]Crystal[/name_f] when I was younger. I even wished that it was my name for a little while, but I find it a bit boring now. I first heard it on a little girl (who would be roughly 14 now but was 4 at the time) who was very pretty, so I actually picture a young girl when I hear it and not a grown woman.