For static meshes actors I can expose all material instance parameters to sequencer automatically. Here’s a quick example - I add static mesh to sequencer → Static Mesh Component → Material Parameter Element 0 → Select any available material parameter and animate it.
When I try to do the same with other actors that have material parameters it doesn’t work the same. E.g. I tried to do the same with Volumetric Cloud actor that has Volumetric Cloud Component that has Cloud Material and it doesn’t allow exposing Material parameters, instead I can only change the material asset itself.