The most often asked questions are What is a monotype? What is a monoprint? and Why do one of something?
For me it is exploring variation and surprise, I work in a series so there is continuity and consistency however I do not enjoy repeating the same image over and over. (Perhaps that is a throwback to my years of production pottery.) I am interested more in the what if factor of creation.
Simply a monotype has no fixed matrix on the plate and a monoprint has an element within the plate, which is repeatable from print to print. As far as the appeal of doing a unique print, there are surprises and new things to discover.