Yes, this intentionally tries to avoid changing the behaviour of existing LookAndFeel classes. The existing behaviour doesn’t feel “broken” enough to change it, and modifying the colour lookup mechanism might silently change the styling of peoples’ apps which I’d prefer not to do without a strong reason.
For now this feels like a good middle-ground between allowing more flexible theming without requiring users to test and rework too much code. Maybe I’ve missed a better solution that would work for more users though, in which case please let me know!