A silicone grip strip is a smooth strip on the back of the helmet that uses friction to hold your goggle strap in place, rather than a mechanical clip that snaps over it. You'll find this setup mostly on freestyle helmets and low-profile designs where riders want a cleaner, more streamlined look.
The trade-off is security. A silicone strip keeps your goggles put for normal resort skiing, but the strap can shift or slip off during a hard crash or aggressive riding. An integrated clip is simply more bombproof — it physically locks the strap down so it won't budge.
Go with a silicone grip strip if you prioritize style and a minimalist feel, or if you mostly ride park and want that clean aesthetic. If you ski fast, ride rough terrain, or just want maximum peace of mind that your goggles won't go flying, a clip is the safer bet.