Truthfully though, I often times find myself wondering if these things are actually the case or just in my head.
If you're from the 60s' - 70s' era, most drum instructors taught using traditional. I've had an instructor literally slap my left wrist (w/ a metal marching band stick) demanding I keep a trad position when practicing on a pad in a flat position!! I was there to just learn rudimental notations and not support his inflated ego. Lol!
Reason is, to some degree, is that these people come from the early jazz or having to play in marching bands even prior to that time. As we know much of the pre-jazz drummers all had their snares at that angle, thus you have the 'practical' aspect of the correct arm angled which is really natural.
It's probable to me then, that in time, traditional became vogue in that it made it 'seem' the universal method even if the snare was at a flat position. In other words, traditional really was incorrect "technically" speaking in terms of it being "practical" in playing for everyone. We've been victimized in believing that traditional is the correct method playing a snare, regardless of it's positioning. And this is where many of us find ourselves playing trad on a flat snare -I do still.
So in answering your question above I would have to say......it's a psych thing of the head. Till today I sense a subtle slapping on my left wrist when in match grip....interesting to say the least. BTW, this drum instructor, rest his soul, built a reputation to being known as a brute of a Russian. No pun intended.