I can install/run Xyce easily enough (the build guide is pretty thorough). ATM we're trying to train up other people on the software, and some of them aren't really "devs", and so aren't familiar with build systems in general. Unfortunately we don't really have full control over all of their run-times, so we wanted to get something easily deployable instead of running support for them when they have weird issues like broken library installs, misconfigured permissions, etc.
I don't see why parallel Xyce wouldn't work well with docker. To my knowledge containers aren't locked to single processes.