Any default animator/animation should be included in the VRChat SDK - Avatars folder and kept up-to-date with what's used in-game. Pretty much what's in the Samples folder, but in a read-only state.
Tools like Av3Emulator utilize the default animators to preview avatar logic in-editor. Other tools utilize these default layers to generate new customized ones. https://github.com/lyuma/Av3Emulator/issues/52
The current Samples folder is easily dismissed as bloat and deleted by those who don't immediately need it. Tool devs and avatar creators need a guaranteed way to access the up-to-date default animators without needing to include their own out-of-date versions.