I think the OP is talking about valve cover gaskets made of silicone rubber, not talking about using a silicone sealer on top of a (regular) valve cover gasket.
Yes I would definitely use a silicone valve cover gasket. Silicone holds up well to chemicals/solvents, heat, cold, age, etc. Maybe other materials (FKM?) that hold up better to chemicals but silicone is very good. Valve cover gasket is a good application for this material.