Is vistaprint and zazzle really necessary?

Well the thing is that I'm not really that interested in the whole T-shirt or designs for sites like zazzle or vistaprint. But they would be cartoony designs such as this ----> http://emeyex.deviantart.com/#/d47reeu

But the main point i'm getting at is that I don't want to put time into setting up these online shops and spend even more money unless it's the smart thing to do. I was wondering if any other designers have experience with these websites.