Sparrow Wallet – Private Electrum Server over Private Bitcoin Core

Help needed in understanding Sparrow Wallet's best practices guideline here –

https://preview.redd.it/z0cxvo2kd8xd1.png?width=1202&format=png&auto=webp&s=6daf4e53875e35c7c3b7cd4c97b7b00b31fce3ac

From whatever I could gather online so far, a private electrum server is needed for an electrum wallet to connect privately because it cannot connect directly to bitcoin core.

From sparrow's documentation it looks like it can connect to both – a private bitcoin core as well as a private electrum server.

I do not intend to use electrum wallet. I intend to use sparrow wallet.

I understand that a private electrum server sits between sparrow wallet and bitcoin core. But I do not understand how this is more secure or helpful than sparrow wallet connecting directly to a private bitcoin core. And why is it listed as the recommended choice for Expert stage.

Appreciate any help addressing this.