Load up any VST 3 / AU plugin
The MP Host (MPH) is a VST3/AU/AAX plugin itself and it can load up third party VST3/AU plugins. MPH allows to load only one third party plugin at a time and there are two versions of MPH, Audio Effects and Instruments.
Its virtual encoders (32 per page, 4 pages, total 128 virtual encoders) can be mapped to parameters on third party plugins and on midi controllers.
Audio passes through the MPH unchanged, the MPH does not process any audio and there is zero latency to the audio signal. The MPH is a virtual midi controller within the DAW, acting as an intermediary between the DAW and the MPH midi controller. Midi played notes and DAW tempo are passed to the third party plugin loaded in MPH.
Seems the MP Host is needed
If that is true, then I fear the same issue exists as it is with Komplete Kontrol.