Because everything he drew was just dead on. I never read a Tom Sutton story where I wasn't really drawn to the art and storytelling. Sutton approached every story with a cartoonist's sensibilities combined with an illustrator's chops--always efficiently done but with enough weird detail (sometimes more than enough) to make you look twice at a lot of images. Sort of like Toth via Wrightson...or something like that. Sutton's art always made it look like he was having a blast.
For a Charton horror comic, this Sutton-drawn story has an unusually coherent and forward-moving plot. Who wrote it? The Grand Comics Database doesn't list the writer, but I'm going to guess Tom himself did the job, because it's so much less a mess than most Charlton stories...the dialog and captions have a cartoonist's economy (at least for 1971, when it was originally published). But I could totally be wrong.