The only use case i can think of is if you have untrusted users on the network...
This, but the problem is that you have untrusted users who you don't even know are users on the devices on network. This includes:
- Botnet nodes on compromised IoT junk
- Developers of whatever sketchy apps you installed on your phone or PC
- Attackers who've already compromised an actual server on your network, possibly a low-value one where security was overlooked
- Physical attackers who discretely connected a device to an ethernet jack somewhere
- Neighbors/wardrivers who guessed/brute-forced your wifi password
- And any of the above using their devices
- Etc.
A fundamental principle of security is that the network layer is always untrusted. If you follow this you will save yourself a lot of trouble.
