It would be super weird. Focusing that much on looks, so much so that you'd have a card printed, is just wrong. It'd creep me out.
Giving out a card like this is strange and socially awkward.
I think it's weird. Use your words. If a compliment can't be given verbally, don't make it awkward by handing somebody a business card with a compliment on it.
You know they bought a box of 500 of them, too, so how special do you feel now?
hmm good point. It's still a compliment though (not a request for a date). I could have easily given 500 of those to complete strangers in a couple of years if I had them with me (not looking to date just compliment someone that is well put together with clothing and attractive to my perception). Still think it would feel creepy though.