There is a priority advantage for a bank to take an assignment of the note and security agreement when someone assigns their filing, but it is not required. Priority can be affected by the terms of the security agreement. This is a little advanced for this forum.
However, in 9-322, the general rule of priority, there is no requirement to have the note and security agreement assigned.
Also, stating that this subject is controlled by state law is a truth. But all 50 states and Washington DC adopted the same law for the general rule of priority, verbatim.