I imagine it also has something to do with convenience. Being such an old game, the technical requirements are quite low, which allows them to easily have that setup of multiple virtual machines on a few servers. Also, I believe they can use the same CD Key for each instance, and it doesn't require a connection to the internet, reducing variables and potential problems.

That said, it would be cool to see SC2 for this, and maybe we'll see it eventually. But I think Blizzard would have to allow it in the end, considering they've been in direct contact with them about this.

Maybe they didn't know about it? First I've heard of it.

Looks really great. I hope they look into this.

Using that on Battle.net violates the TOS. So your account will get banned if you do that.