Depends on The Person who's wearing it...sometimes it looks very badass but other times it looks just bad. I would personally never get one because i feel like if i got a nose bleed or something it would be gross.
I think people mix up freedom of expression with freedom from judgement. Yea, you can wear it, but but people are free to make judgement's about you based on your appearance.
Do not poke holes in your face...not ever. Not pretty and when you stop wearing the jewelry, you just have holes in your face. Not pretty. I repeat, not pretty.
http://www.nairaland.com/attachments/1470845_do-cows-rings-noses_-800x800_jpgf3fa79d7910abbf59a111569444fc782
Whenever I see anyone with that I want to say "el toro" and wave a red blanket in their face