Both my boys were tattooed while asleep for their neutering.

I found this about microchips:

What is Microchipping?

"Microchips" are small computer chips about the size of a rice grain. A veterinarian injects the chip under your cat's skin. Most cats tolerate this minor procedure with no problem.

The chip contains your cat's identifying information and can be read by a special scanner. If your cat gets lost and is taken to an animal shelter, most shelters can scan the information on the chip, identify your cat, and get her home to you.

Having your cat microchipped is a good way to help her get home if she ever becomes lost.
The article goes on to say to add a collar and ID tag.

As for tattooing and piercing pets for 'fashion' reasons, no. I can't see your post right now so I don't recall if your friend was joking - but if he wasn't, his ego is bigger than his heart. ("Hey, look at my pet!!! See what I had done! Isn't it COOL?" That's all about the owner, not the pet. JMO)