After getting into mobile app development, codepush was something that grabbed my attention right from the start, so much that I ended up setting it in our company and writing a tutorial on how to use it.
This saves us so much time & hassle when it comes to releasing an update. Now, instead of pushing new app to the store and waiting Apple / Google reviews, we push it to the appcenter and our users get it automatically.
As a bonus, appcenter also gives analytics and crash reports (although not as elaborate as bugsnag).
If you are working with mobile apps and (somehow) never used it - it's a must.