Since we're syncing from one DB to another, we want to keep the Record IDs the same in EE and Core.
The EE Import ID is a long number that's coded by default on the EE record. We have our own Record ID that we manually input in EE when we create a new record. That's the number we want to port over during the sync between EE and Core.
Not a bad idea, and something I considered for our own schools, but I found after reviewing it all that the better ID to use for syncing is in fact the EE Import ID - our students sometimes move between locations and their Student ID can change based on their location. By using the EE Import ID (which won't change), it retains the sync with ConnectEE and doesn't create a new record for that student.