The purpose of the app is to allow you to control a Windows or Mac desktop from an iOS or Android device. Hacks that have allowed you to do this through VNC have been around a while, but they haven't been particularly user friendly, and the security was maybe a little problematic.
PocketCloud comes with two clients, one for the desktop and one for the device, that talk to each other through the PocketCloud servers. As such, there is no need to punch holes in the local firewall. You must install them both with the same Google account (at least for my Android) so that they are seen as a pair. Two factor authentication (you are using that, right?) is supported through Google's permanent app password feature.
It really only took a few minutes to have it downloaded and running on both apps. Once paired, I accessed my desktop from the tablet with the same credentials I usually use. A finger-draggable multi-purpose mouse-like-thingy allowed me click links, close windows, whatever. I had pretty much full control. It was just that easy.
The application settings were surprisingly full featured. I could display different aspects of the desktop, choose where to send speaker output, choose how to initiate the keyboard pop-up, and tweak various local interface options.
If I have to pick an imperfection, the display aspect wasn't a great match for my tablet, and I could only pair with one desktop. But both of those limitations go away with the paid version (15 bucks, one time) so even that is no biggie.
Overall, I'd have to say this is some pretty useful technology. Kudos to the developers.