If unique, decentralized, human meaningful names are impossible to provide otherwise (to our knowledge), and such a thing is desirable (I hold that to be self evident) then "why not?" indeed.
If you're afraid of being called a shitcoiner, Namecoin was the first alt, came out of a satoshi-endorsed proposal, and never positioned itself as an investment, although I don't know if the project is dead or not, it's been on life support for a while.