Sexual desire is a basic part of human nature. Trying to ignore those basic instincts can result on huge mental stress. Porn allows relieving this pressure without forcing people through the act of finding a suitable partner, which is something that is not always easy for everybody. This also means that it's a tool to reduce sexual crimes for people with poor self control, or disturbing fetishes (particularly for the latter drawn porn is a solution that allows living out these desires without harming anybody).

Ultimately I believe that the wide variety of porn is healthy for our society. I'm more of a cuddling guy I admit, but I see its use and don't think that is something we should condemn, but be grateful for.