You’re correct in your understanding. It allows standard discovery (the platform script commands and the slave) to proceed but blocks the calling of additional commands from TPL.
In practice this will cause discovery.runCommand, discovery.fileGet, discovery.registryKey and discovery.wmiQuery to return nothing and be marked as a failure. If you look at the failure_reason attribute on the node the reason will explain that this option has been disabled.
This information is also shown when you view the DiscoveryAccess node so it is clear what has happened. I’ve attached a couple of screen shots to show this, note that the text of the message is slightly different as one is from a 7.1.5 release and the other is from our internal 7.2 test machine.
As to what the behaviour of the pattens is when you enable this option is down to the pattern. Generally if the discovery call was recovering non critical information like version details they will still work you just won’t get the data.

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