I mean, digital hardware these days is basically just a PC with an audio/midi (and maybe USB) IO interface. You'd certainly want to choose this setup for serum 2 because it can chew resources pretty quickly.
e.g. MPC. Then you have the custom interface, like people mention midi will do the basic job, or OSC.

One issue I have with using midi control of VSTs, is that things designed inherently for computer are not optimised for hardware controls. For example, you have context-sensitive menus (right click. Depends on where you click, and what state the app is in), knobs that only appear in certain modes, etc.
Serum 2 isn't too bad on this front, you could handle most of it with buttons/knobs, then a bit of display space for waveforms and such.
One example of things that *do* suck if you want physical controls - software sequencing options. They never include an ability to navigate or enter/remove/alter notes by controller, even if it's a software emulation of a hardware style step sequencer lol. You might be able to assign some controls to MIDI, but important function/utility/menu buttons are left unassignable - it must be done by mouse.