[SpiegS]

Never needed to do something with layer2. I used it mostly for educational purposes for my home network. Can you name some real world examples when OSI layer2 filtering is needed?

[ryan-c]

I use layer 2 filtering on my home network in order to get direct internet access without going through my "mandatory" ISP-provided gateway that authenticates the port with 802.1x EAP-TLS.

[BrandoElFollito]

Containers connected to a common bridge, for which you want to restrict traffic (between them). You have to do that at L2.

[nisa]

mesh networks that use a layer 2 routing protocoll - or if you have VPNs that use layer2 and you want to filter the clients on the VPN server bridge.