I have a quick question that's bugging me the more I read about VLANs.

So far I understand that they are useful for dividing the network into sub-sections, but if you route them together does that not remove any security benefit?

As an example, if I created a VLAN on my home network which was simply one computer, one server and one router.if I wanted to divide the network between computers and servers I could put the computer on VLAN 10 and the server on VLAN 20. Then the computer would no longer be able to communicate with the server - unless I added a static route to the router that connected the two together, basically telling VLAN 10 that VLAN 20 exists and how to communicate with it.

The VLANs would then be connected in a similar way to a 'flat' network that has no VLANs. Therefore, surely, all security benefits are lost.

Am I missing something?