You're missing the forest for the trees. The issue is not building an app specifically with Electron, but building an app which requires a browser. The browser is expensive in terms of resource usage, which results in less battery life.
Using a browser is OK for an app intended for a light usage session (like booking a flight). But not OK for an app which is intended for heavy usage sessions (like browsing pictures in an infinite timeline).
There's a reason Slack (which already has a reputation of impacting your battery life) decided to create a native app for mobile instead of using an Electron-like framework like Capacitor[1].
> Apple’s restrictions on third-party browsers, and the limitations it puts on Safari/WebKit (its own browser tools) have hobbled “web apps,”
Though I'm sure you can also ask many product managers how well native apps on iOS perform due to web apps (many companies have data on both). For whatever reason, users prefer native apps
Plus most of those website "apps" are just a bunch of webviews anyway, so you're not going to save battery by using them. Just like Electron.
Answer: Well obviously, since landlines are missing the biggest feature mobiles phones have: portability.
Point I'm trying to make: 1. Apps are smoother than web experience 2. Have a much native-er feel, etc.
If app is available, I'd rather use an app.
A big thing would be notifications, which at the time of writing is still an issue but slated to be corrected next year.