The Legend of Korra, Book 5: It's canon. Deal with it.

[Zevox]

It doesn't, but it certainly makes watching their interaction in Season One with knowledge that they'll end up together very amusing.

But that would require re-watching season one in the first place.

Generally speaking, as awful as the love triangle was, I think they managed to turn it into something good, eventually. Not just because Korra and Asami ended up together, but because Korra and Mako's breakup was handled surprisingly maturely. They fell in love, but then they realized that it doesn't work. Things got awkward, but they moved past it and remained friends, with Mako promising that he'll have Korra's back no matter what. In a medium where people staying with their first crushes forever after is the norm, it's pretty refreshing and valuable.

That's true enough I suppose. It just still isn't enough to make up for having to sit through the initial love triangle in the first place, as we've both already agreed.