Okay. Now for the one big background observation: SINCE WHEN CAN SWEETIE BELLE TELEPORT!

This is significant to me because for one of the few things that has been relatively consistent in the series on magic was the implication that teleportation was a vary high level feat. I do not think it was till season 5(?) that we had not seen anypony else teleport besides Twilight Sparkle, Celestia and Sunset Shimmer. From that point I'm trying to recall of any instances of a pony who was not at least somewhat magically gifted and though season 5 through 7 are a bit more of a blur to me I do not think we've seen anypony violate this rule. From an in universe perspective what does this mean? Does it mean Sweetie is magically gifted? Has she been shown to have done anything beyond a some latter season moderately advanced feats Rarity did before (though perhaps Rarity maybe more of above average and not a benchmark for what an average unicorn could do with skill). There is a possible cannon path with the whole somewhat vague "magical power is based is on what you feel" but still sense visiting that there has been both implications of feats based on skill and someone who is naturally powerful/gifted in the show. Maybe their is some instance I'm missing but from what I can recall this is still pretty surprising given what all we know and have seen.

The out of universe reason: I just think the show staff wanted to have Sweetie Belle teleport.