There are now numerous VST plugins which provide functionality that pertains to the final output of an audio interface. For example, Sonarworks performs room correction functions. Audified MixChecker offers simulations of various speaker outputs. Several NUGEN and Brainworx products are designed as control room tools (soloing mid/side and L/R, flipping phase, etc.).
For some of these tools, the only place a user wants them is at (or near) the very end of the signal chain. They don’t really need to be in a DAW; they’re designed to be applied to the final outputs so a user can apply them to the full mix.
Beyond mixing, many of these tools would be useful system-wide, so that they would apply to general system audio as well as DAW output. Currently, there are a few tools that can help achieve this goal (Sonarworks Systemwide; DDMF Virtual Audio Stream; VBaudio products; etc.). But these products act as drivers themselves, so if you’re looking for the performance and features of the native UR ASIO drivers, you have to choose. So a user ends up with a hybrid situation where monitoring-stage plugins are (a) applied manually in various ASIO-driver-using DAWs; and (b) applied globally via Virtual Audio Stream, etc. for programs that use basic OS-level audio drivers.
Some problems with this hybrid use approach are that the user must:
a) remember all the various ways that the monitoring-stage plugins are instantiated, ensuring that they never overlap or conflict;
b) manage non-synchronized settings of various instances of the same plugins across various applications;
c) because the plugins might perform differently in the various uses, the settings might need to be tweaked for different apps (inconsistency);
d) these workaround virtual cable solutions tend to be unreliable/buggy;
Steinberg could solve this problem by simply including, as part of the UR drivers and software, a VST plugin host that can be applied directly to UR hardware outputs. This way, regardless of how the UR hardware is accessed (Yamaha ASIO; ASIO4ALL; OS sound drivers; etc.), the UR hardware drivers/utilities themselves would be responsible for applying the VST plugin processing. Thus, literally all the sound coming from a computer system (system audio, DAW ASIO audio, music players, etc.) would be processed through one set of plugins.
Taking this a step further, ideally the plugins could be applied to individual hardware inputs and outputs. Essentially a full routing matrix could be applied. But these would exist outside the DAW and would apply to the hardware itself.
Advantages: One set of plugin instances. One batch of settings. No buggy third-party solutions. Consistent performance.