Not lighter weight than a website because it is a website. The only advantages are you can ship parts of your app as native code, and you aren't constrained by the browser permission model.
One interesting usecase is that you can run a tauri app without any webview windows just as a system tray icon and only spawn a webview window when necessary.
This kind of makes it way more lightweight but only in some situations (obv. heavily depending on the functionality of the app).
Would this be for a service style app that happens to have a UI when you need to configure it? If so that's an... interesting idea, but considering the UI is less important I'd probably mind it less (as someone who is not a fan of Electron apps).