For networks I understand we set a netmask on each computer to let it know what IPs it can talk to without going through the router - IPs on the same subnet can talk directly to each other and do not have to go through a router/switch. However, in today's home networks (and I suspect corporate networks as well) every computer is connected to a router/switch (at the low cost of today's hardware I doubt there it much of a market for wired repeaters/hubs). This seems to obviate the need for a subnet mask and subnetting.

Considering that in most modern home architectures every computer goes through the router, even to talk to computers on the same network, is there any reason for me to subnet a home network?