Why does does an interface on the internet switch still allow devices to access the internet when you shut down the associated VLAN?

This may be a dumb question but I'm a noob trying to wrap my head around it. We were testing a failover on an internet switch so I mistakenly shutdown the vlan interface on the switch instead of the physical interface with the vlan on it. Why did the internet still work after shutting down the VLAN? I realized this didn't work and after I shutdown the physical interface with the VLAN, the pinging stopped.