I enjoy writing them, which is what matters most to me. And I like having a place to write about topics that interest me but I don't have time to write about at more length.
Philip Roth was a perfect example. I like his work and know a fair amount about it, but writing a long piece would take me days, because I'd have to go back to reread so much. Writing a one- or two-minute piece was perfect.
My short pieces also typically get a high read ratio, whether I do them here or for Everything Shortform or The Daily Cuppa. If you're thinking of doing short pieces over at the Pub, I recommend it.