Themes allow customisation of AAF animation Packs by adding tags to installed Animation Positions. If you do not install some Themes, there will be no tags added to any relevant animations you have installed so they should not be picked by mods using the tagging system like Violate or RSE. So if you want to install an animation pack that has a mix of Human and Creature animations, this means mods can tell the difference and only pick the ones that interest you by its settings unless you manually