This service provides a tempoary home for services which need to be available prior to appmgr being launched, but don't want the tedium of setting up their own process. These services previously were hosted by svchost, but has proved problematic, so they have been isolated into a separate process.
Services implemented by miscsvc are exposed to svchost, which exposes it out further to other parts of the system.
Once component manager lands in bootfs, and adequate build support arrives, these services can be rewritten as components.