What is so great about Reddit/Lemmy apps?

I'm desktop-only user and never had any experience with Reddit/Lemmy apps, and the sentiment towards them confuzes me.
I can imagine that the third-party apps for Reddit were better (?not bugged?) than the official one. But what made you to love them? Was the experience even better than desktop use?

Feel free to write about both Reddit and Lemmy apps in your responses.