Needing to run games on the same machine as your server is IMO not the most common use case. It tends to be expensive if power bills are a concern and using a VM as your main machine is tricky IMO.

Most games using anticheat won't run on VMs without a fight too. Your Proxmox supports taking a memory snapshot and restore, which would allow most cheats to work if they are convenient enough.

For every person like your brother we have many more half-serious people who need some type of reward before committing more mental effort. Wtf is a storage pool? What do I do with all these clusters, high availability thing it keeps asking about? Flattening out the learning curve is a nice benefit on its own.

The machine that I use now for my server was my main machine back in the day. Apologies if my wording in the post resulted in some confusion but I don't do gaming on the server at all.