Why have this app when it doesn't really add any extra value to the functionality that Gmail offers itself?

Because email shouldn't be a place of focus, not compulsive checking. This app helps me get it outside of my regular workflow and make it a special place for email.

I'm already using a SaaS Manager like Wavebox but, Gmail in there makes it a mess... It's the only thing I spend my time with, going through all the spam these tools send me... (YES we love your product but we can't read all 100 apps daily emails...).

This tool is my Gmail Manager as an App that avoids me to use it inside the browser. I don't use any SaaS tool in my browser that's inside my WORKflow... I do use tools to study, learn, and get to know them until I know if and how it should fit inside my already overwhelmed workflow.

Big problem solver this tool, even though if you look at my comments in the questions, didn't understand it, until I did :)