Certainly,

First of all, this points out this assembly is specific to a structure with timber framed walls. Such roof framing is common on log buildings and also known on stone walled structures. In these, the nature of the walls more or less eliminates the need for such a cross beam. Timber framed walls, being naturally unstable, require cross beams to brace against the pressure of the rafters. In a log structure, for example, you would just put the rafters directly on top of the log walls and trust that the partitioning walls are sufficient to brace the structure against the inward pressure.

This is a direct comparison to a roof with no ridge and seated rafters. Such a roof as discussed has an anchor beam or tie beam designed to resist outward thrust.
The 'Drücklastig' roof instead has a simple cross beam that braces the walls against inward-working of the rafters.

To resist inward pressure, all you need is a stick to push against it (remember Newton's third law) whereas to resist roof thrust, you need a heavy beam with complex tension joinery.

Drücklastig = inward working (literally, press-loaded)
Schublastig = outward working (literally, thrust-loaded)

So we can think of things in terms of 'Rafter pressure' or 'Rafter Thrust'