ThreadSafeReference vs Primary Key

If I have a primary key for my model type is there any benefit of passing a ThreadSafe Reference instead of just passing the key?

The documentation states, " Prefer short-lived ThreadSafeReference s as the data for the version of the source Realm will be retained until all references have been resolved or deallocated."

Assuming my primary key is pk.

let crk =
let crr = ThreadSafeReference(to: oldFoo)

This line:
newRealm.object(ofType: LedgersDB. self , forPrimaryKey: crk)

Seems about as fast as this line

Does the resolve bring along LinkingObjects more efficiently or something?