It's not prohibited from a technical perspective to share the NWC that was created when Navisworks cached a CAD file (I am presuming you mean with other people?). It's a perfectly valid NWC file at time of writing. A lot depends on how your workflow fits with the conversion stage of getting data into Navisworks. Forgive me if any of the following is old news:
Overall our expectation is that if the user is dealing with CAD files that are converted via loading into Navisworks, they'll open it, save an NWF linking to that CAD file, and the cache file is effectively an invisible convenience. The motivation is that the NWC files (from either route) still only represent pure converted CAD data. When you want to add data that Navisworks itself stores, that goes into the NWF (which then does things like track CAD object identity). As a result, our ideal scenario is that the shared elements for use by teams would either be the CAD + NWF files as source (e.g. a designer now needs to modify the combined model or elements of it) or NWDs as snapshots (a coordinator needs to review a given state of the combined model at a point in time).
A side-benefit of this approach is that if the NWF does refer to an NWC directly, it's clear that that was from export, and otherwise, the NWF links directly to the source of CAD data without user hassle of extra steps to convert the file. Navisworks can overwrite or re-generate cache files if it feels it's appropriate; NWFs that link to CAD files directly can automatically update.
So, in summary, we tend to encourage people to ignore cache NWCs specifically because they're generated by side-effects rather than a deliberate action on the part of the user, and because we hope that the alternative route is more convenient - one click open of the NWF takes care of everything bar the more awkward exports (which we can't easily automate from within Navisworks - at least not yet).