Immediate desire/need:

I have some devices on my network that I would like to limit, and it would be neater to have their MAC addresses in a list such that the Bridge Filter would have a condition called "Src MAC List". This way I could simply add MAC addresses to the list, or remove them, instead of having multiple Rules.

The IPv4 and IPv6 filters could also implement Src MAC List / Dst MAC List, which would mean I can more easily control the same group of resources across both IP versions.