No, CSSU is just a repository. You can update all it's packages manually when they come out, without mp-fremantle-community-pr. The latter does nothing on it's own, except for that system info under configuration.

The rule of thumb (and universe) is that everyone, at some point of time, will end up getting rid of mp-fremantle-community-pr, due to it conflicting with whatever operation one just want to perform. Following it, if you're doomed to do it anyway, in weeks, months, or years, you might as well do it now. You won't miss it.