Yes of course it does. Fury, AJ, and Wilder would not be this successful if they were short. Of course there is plenty times where the shorter man wins, but height brings in a big advantage for the most part. Like others have said, if you know how to use it, its a really big deal
Take away PEDs and you'll see how much stature matters. There's a correlation between height and size, though not direct, but still there, obviously. Size let's you take more damage and give more, generally speaking. Canelo is only able to go up like this due to chemical enhancement that is on a different level to average pros. What's happening now is so crazy and still plenty just act like nothing is going on. This guy was dragging Khan up not too long ago, saying he wasn't ready for MIDDLEWEIGHT.
That doesn't matter if they're not legit heavyweights or not. Your argument is height. If the fight was at heavyweight then it's a heavyweight matchup with two heavyweights regardless if one of them is a blown up lightheavyweight.
It matters. There will always be some short guy who is so incredibly gifted in other ways that he can be a giant killer, but that same guy would be better if he were taller and had a longer reach.