Any functional differences between "System boards" and custom boards?

By “System boards” I am referring to those that come pre-built in Monday (Contacts, Accounts, Deals, Leads, Client Projects, etc.). They are identified in the underlying JSON with:

"system_entity":{
            "entity_name":"account",
            "is_deletable":false,
            "is_system_entity":true,
            "columns":[

Custom boards appear to not have this declaration.
Also I am aware that the pre-built / system board do not have the Duplicate Board feature available. So that already tells me they are in some way treated different to custom boards.

What I could like to know if is there are any other differences in the way these system boards handled compared to custom boards. If, for example, I set up a custom board for Contacts and Deals, other than gaining the ability to use the Duplicate Board feature, is there anything I might be losing in terms of features / functionality?