I’ve just realized that this Understanding Dependencies in AYON Addons and this What are dependency package and how to update them? are lacking explaining the difference between dependencies → [tool.poetry.dependencies] and runtime dependencies → [ayon.runtimeDependencies].
Pillow is a runtime dependency in ayon-core which if I’m not mistaken means it won’t be propagated to the DCC apps. these are type of modules that we create wrappers for them like opencolorio .