The big problem with trying to separate between a VTT and a videogame is that at least 2 of the biggest VTTs are arguably generic programming frameworks. Both Foundry VTT and pro level Roll20 allow for adding essentially unrestricted javascripted features to your VTT experience. In that regard the VTTs are a bit like for instance Unreal engine. They are arguably not a game themselves, but they can both be expanded to become videogames.
As such allowing "any use with VTTs", and then go on to try to define VTT is a framework that seem futile to use if one want to accept any of the currently accepted VTTs, while preventing use with any potential future video games. It would seem like a more natural approach would have to look at who actually uses the vtt along with srd content to create a "video game" experience.
To exemplify: If we for the sake of argument accept the laughable proposition that the display of a moving magic missile somehow is what differentiates a "table top" experience from a "video game" experience, the policy need to state clearly that if someone is using a provided VTT compatible compendium of SRD content with a VTT, along with a modification enabling spell animations, neither the VTT provider, the compendium provider or the provider of the spell animation package is in any way "at fault". For the current situation hence the only one wizards could reasonably target with C&D or other legal actions would be individual GMs.
However going after GMs like this seem like both a highly unpopular move, and practically not really enforceable. It would also make it impossible to go after the main target - someone making a full fledged video game "template" package, only requiring the insertion of monster and spell data of a "certain format" to run on the VTT as an actual proper video game.
In other words, in order to achieve all 3 of allow existing VTTs, prevent de facto SRD use in video games under the VTT policy, and being able to target anyone save the actual end user for infringement, some really creative framework of thinking I can't see for the time being needs to be applied to the policy.
My working hypotesis is that it just cannot be done.