T-shirts are in a similar ish vien to stickers in terms of there's a lot of variables to consider before making them. On the one hand there's many options when it comes to having them produced again print to order comapnies are well established, however there are other factors which come into play. Firstly the deisng itslef has to work for a t-shirt as in it needs to fit a basic template, additionally the materials/ quality of the tee are important. You could get 100 tee's for cheap but if they're poor quality its no good. However, having an actual product that can be worn and used daily means its got a wider target market, anyone can wear a funky tee they dont need to be a fan of the exact design.
Overall t-shirts have there own set of pros and cons that need to be considered before committing to a concept.
.Small, easy to have made.
.Works well for anime designs.
.A variety of options for finishes
.Often have to be bulk ordered
.small profit margin
.Easy to make/ to adapt from a concept
.Print to order options
.wide target market
.Dependant on existing audience/people who already follow you
.Variety of variables to consider
.Wide target market
.Easy to produce via print to order
.Quality needs to be considered