News Courtesy of cPanel.com:
What is the cPanel App?
The cPanel App is an app for Android and iOS devices that allows you to manage your cPanel & WHM accounts. This app is available to provide quick and secure access to the cPanel & WHM services for your server, without storing passwords in your browser, or manually entering them every time. Though powerful, these apps aren’t meant to completely replace your normal desktop interactions.
Ryan’s Take 
While I’m not familar with cPanel’s own mobile app, the popular WHMapp is fantastic. You won’t have the full suite of options in WHMapp as you would logging into your browser, however, simple changes and monitoring can be performed for administrators who like to frequently keep tabs on their server. Honestly, it isn’t something I use too often. I usually, have my laptop with me in case of an emergency website issue happens to a client of mine. Although, the app has been a life-saver on a couple of occasions.
Since I’m big on security, I use several plugins on both the site level and server level to help protect against attacks. Sometimes, due to the high-level security rules I have in place, I get locked out of my server. Basically, my IP address gets blacklisted and put on the naughty list. In effect, banning me from my own system. This is where the app comes in handy.
On my android phone, with wifi turned off, my IP address changes to that of my wireless provider. I’m able to connect to the server through the app and clear out my block list. Typically, it is ConfigServer Security & Firewall that needs to be adjusted. I don’t mind the occasional ban as it is excellent at blocking legitimate attackers. Sometimes, it is actually my own fault for inputting incorrect login credentials too many times!
