nNowadays the 3/4 plate seems to be used more and more for marketing and some try (successfully) to create a symbol of German watch making. I think this layout was used all over the world and e.g. English movements are typically very closed to 3/4 too.
And in my opinion there is
a technical reason for this solution and it's not "only" tradition.
To understand the reasons, why the German and especially the Glashütte watchmakers choose this layout, one has to understand the typical German approach to technical solutions: reliability, and "bullet-proof" dimensions of all components are priority (at least in former times).
This said, you may imagine, that there are very few German-made movements, which could be told "flat" or "delicate" in the sense of the fascinating fragile and very "dressy" movements the Swiss already made at the same time.
The typical German PW movement was a real big and heavy one.
Just to have an impression of some PW movements, there you see a typical English, a "Glashütte-style" and a Swiss bridge-type (typical LeCoultre style):
One reason for the 3/4 plate is more obvious if you have a look at the anatomy of a bridge plate combination on a classical bridge-movement:
Any of the bridges and cocks needs at least two of these "fixing-pins" to make sure that the part is in the precise and correct place.
Having a lot of single bridges/cocks means a lot of holes, to be drilled with the best possible precision.
The 3/4 layout is amazingly simple, just a few pillars (in this case it's the English movemment) with a small step at the end resting in the hole for the plate screws. Simple, reliable and precision is achieved much easier. The bearings for the complete gear train are combined under one plate.
If built precise, it will stay precise for the whole life.
The beauty of the plain, seemingly "simple" 3/4 plate with it's mostly frosted guild finish, is perhaps a little more subtle,.... but I really love it.
there are typical national characteristics (I think yes), they are much more found in technical details and the realtion of the dimensions (IMHO)-and,....lots of these characteristics are lost in the last, maybe 40, years.