It's not like they're trying to cram in a music player or IDE in to an Electron app. This is a browser so I wouldn't expect the load to be substantially worse than running Chrome.
And you wouldn’t expect atom to use more memory than sublime, either.
This is different. Atom is a text editor implemented in a web browser engine. This is a web browser implemented in a web browser engine.
I wouldn't expect it to be any better either. Which means this thing is missing the point of writing a new browser.