Having a icon-192x192.png is mandatory for any site aiming to be installable as an app.

: This icon is defined within the manifest.json or manifest.webmanifest file. Browsers use this manifest to understand how the app should look and behave when "installed".

Modern flagship phones (Pixel, Galaxy S series, OnePlus) fall into the category. When the Android launcher requests an app icon for the home screen, it requests the 192px asset and scales down for lower-res devices. Scaling down is clean; scaling up is blurry.

: While Apple often prefers 180x180 pixels, a 192x192 PNG is frequently used as a compatible "apple-touch-icon" fallback for high-resolution iOS displays. Key Technical Standards

Many developers ask: “If I have 512px, why do I need 192px?”

You cannot simply resize a logo to 192x192 and call it a day. PWAs have specific requirements.