Because it makes me slow down and gives me the opportunity to be a simple human being part of the action, rather than an outsider. That's my take on it.
So to answer to the question, I still shoot on film because I did not, until last week, had a DSLR. I had a few mirrorless, which I did hate (Olympus PEN gives the least real colour rendition possible, Fuji is plagued with industry's worst battery life and autofocus lag). I had a Nikon F55 and a F5. Film is cheap. So I did still shoot on film.
There is also some unique trait with film. The colour rendition is spectacular. There is no match to it !