If I'm trying to run it get somewhere to do an important thing quickly, denying mobility is a pretty big win for the other side. I can think of a few recent fights where misty step was pivotal to the fight for the players. A counterspell would have been bad for them there.
And it's because of this rare scenario that you are going to spend all kinds of time seussing out the "correct" methodology on action, bonus action, and reaction spells so that things are exactly proper as per the WotC-written and WotC-intended rules? Hey... if that floats your boat, go nuts. Personally... I find that sort of worrying to be a waste of my time and my brainpower having to remember all that crap.

If a wizard needs to get across a chasm that fast and tries to Misty Step it and it gets countered? Well, dems the breaks of adventuring. Luckily for him of course is that he probably has another 2nd level slot next round to try it again. Same is less likely to be said of the enemy caster. And even if he does... those two counterspells removed the possibility of 50+ points of fireball damage being rained down upon them in those two rounds. So again... not exactly a loss there in the long run.