Yeah splats can encode view dependency without SH, but not with a correct geometry. E.g. often, you see reflections encoded in GS as just a 3d scene on the other side of the mirror. Other view dependency effect can make the surfaces "fluffy", etc. This is not great when you also try to get decent geometry.
That said, I don't think SH are the best way to represent view dependency. Other approaches using MLP or deep features seem more promising.
They’re fundamental to the scene if you recite light transport and not just geometry. Gaussian splats are just a clever way to sample a lightfield and reflections are part of the lightfield.