sv_pure, when set to 1, will check a whitelist file and determine which resources are permitted indiscriminately from the local client, which have to match those present on the server, and which have to be fetched from the Steam cache. I'm not familiar with using sv_pure for mod resources, but the '1' option seems as if it'd permit mods to function perfectly fine with the appropriate whitelist. Even if that isn't the case, regular materials, such as walls and prop skins, that are not altered by mods can almost certainly be restricted to stock by using sv_pure.
As far as time/benefit goes, crafting a fairly simple whitelist to fight people who cheat seems to me like it'd be worth the time.