Why are Balsamiq and Sketch treated like rivals?

I own both Sketch and Balsamiq, and did a lot of research to find out "which is the best" before purchasing them, but at this point (to me, at least), it's like comparing pencils to keyboards.

I see Sketch as one of the best alternatives (and possibly a superior tool) to using Adobe Illustrator for setting a proper aesthetic tone for a UI, however, a blueprint is a blueprint and Balsamiq seems to do everything right in that respect by not hindering the functionality with unnecessary aesthetics at that stage of the project.

Colors and visual "flavors" are extremely important, but ultimately, it's all about figuring out why they're needed as opposed to where - which, in my experience, should be applied after the composition is better refined for designers by a team responsible for the functionality and logic.

We tend to push pretty things at management and clients too often, when it should be nothing but a black and white outline that helps determine that "this is the way things should work" - which, from an interactive standpoint, is the strongest quality of Balsamiq. Then, when it's time to truly time to "ink and color the finished pencils", that's where Sketch is the tool to move to (which unfortunately is limited only to Mac users, and should no longer exclude those who don't work within an environment created exclusively by Apple.)

I use Windows, OS X and Linux. Like people, when you get to the core of what they are, they're alternate versions of the same thing. But, this does not seem to be the case between Sketch and Balsamiq.