It is very clear from the beginning of the series that Spike has an enourmous crush on the fashionista Rarity. He does all sorts of things to get her attention, and Rarity is always grateful, giving Spike some gems or tokens of appreciation. I underestant why it is a ship. It may not be very popular, but I think that it's very cute.

I rate this ship a 7/10

(Because Spike is a little bit too obsessed with Rarity and in the Equestria Girls world there aren't many moments with the two of them)