The implementation with Electron, as most cases, sucks.
I work with a startup and they have a hybrid app, which binary is 3.5 megabytes [1]. UI is JS/HTML/CSS and is almost the same bundle as the web version [2]
Trello's app is 66MB [3]
1: https://itunes.apple.com/us/app/ninox-database/id901110441?m...
3: https://itunes.apple.com/us/app/trello/id1278508951?mt=12