There would seem to be a logical case for the USMC to put the first F35C squadron on a carrier.
If the USN is happy with the F/A-18E/F in the near future and the legacy Hornets are getting too expensive to maintain, financially it makes some sense and builds on the USMC's knowledge base from operating the F35B.
Then when the USN is comfortable with the performance and integration into the CVW of the F35C, squadrons can be generated or transferred over to the F35C, which by then may have reduced in price.