MST allows to configure a multi-seat setup without the requirement to use a separate GPU for each seat; you can theoretically have as many seats as the sum of your GPUs outputs.
The project was started because the existing multi-seat solutions (that we were aware of) were either proprietary or clunky at best back then.
Currently I don't getting any funding for my work on MST but I'm hoping that the project will be of some help for people.