If you are a Singapore Airlines KrisFlyer Elite Silver, you now get an extra 10kg (weight system) or 1 piece (piece system) of luggage across all classes when you travel on Singapore Airlines. The piece concept applies to and from the USA only.
You also get the extra 10kg when travelling on their low cost airline Scoot, but only if you are transferring to or from a Singapore Airlines flight. KrisFlyer Elite Silver travelling on standalone Scoot itineraries will still get the standard 5kg extra allowance when you purchase 20kg of allowance.
This benefit does not extend to flying with other Star Alliance carriers as that is dependant on Star Alliance Gold, not Silver.
KrisFkyer Elite Silver will also get priority boarding, being allowed to board at the same time as premium economy, KrisFlyer Elite Gold and Star Alliance Gold members.
Oh wow a silver membership with actual perks rather than just a name!