Correct.. You need to connect your Sparrow Wallet to an Electrum Server. This is already the case. Some of us are running those servers, others choose to connect to public servers , thereby seriously damaging their privacy setup, because you share your xPub (all your adresses) with the server for the wallet to function. Frigate is an attempt to create an electrum server implementation especially designed for Silent Payments (and more). So in other words: Frigate+Sparrow = privacy go up. Especially if you run both yourself.