I might be new to the Teen Wolf fandom but I can see why fans have shipped these two together. They have an easy chemistry that could eventually develop into something more. I would consider their relationship to fall in the slow burn trope category.
With the show already in it's 6th and finale season and Derek (Tyler Hoechlin) left in the 4th season, it will be truly surprising if at the end these two somehow become canon. I highly doubt it but who knows maybe Derek will return for a cameo and it will be a surprise scene like the end of Dawson's Creek where Joey Potter ended up with Pacey Witter. That truly was a surprise because everyone thought Joey and Dawson Leery were going to be together at the end.
Anyway, whether or not Derek and Stiles eventually become canon they are a favorite couple to a lot of fans.
Artwork: I Just Kinda Miss This by K2Karine