From the Store entry:
Revolutionary file manager reinvented for productivity on mouse and keyboard, touch and ink devices. Use cards, zoomed out view and workspaces to navigate your huge collection of files and folders as easy you would navigate Google maps.
Instead of watching just one folder in Windows File explorer or two folders in 'Commander' apps, add as many cards as you wish and see your device at a glance. Create your own workspaces as a group of logically connected cards/folders to easily switch between various segments of your data. Searching through the workspace with File Cards tools (where you may enable to see items contained in all subfolders, or filter all the cards by the file type) is the quickest and most intuitive way to find the files as you organize data in the app exactly the way you think about them.
The app brings state of the art multiple windows management with ability to drag a card to rearrange its position in the current window, to move it to another window, or to create a new window. All classic file and folder operations like delete, cut, copy and paste, opening of folders and files, creation of compressed files and their extraction (.zip, .7z, .rar, .gzip, .tar) are reinvented and refreshed. Reminders will help you not to forget to complete your tasks, even if the app is not opened and the live tile will remind you on the pending work.
Some screens of File Cards in action under Windows 10 Mobile, showing the level of detail and functionality:
Thinking about Continuum on the Lumia 950, in particular, it promises a PC like experience, but depending on the app that you use, it might or might not be truth. File Cards is one of apps that delivers on this promise, allowing you to manage complex file and folder structures from your phone in a desktop like environment when used with Continuum. The built-in Windows 10 File explorer is quite basic and doesn't even support clipboard functions, and being able to see only one folder at a time can hardly compare to the PC like experience.
Probably the most important function of File Cards is in its ability to show unlimited numbers of cards (that usually represent one folder, although there are also Recent and Bookmarks cards) in one screen. That way one can have an easy glance over the contents of the folders, that in some way goes even above what is offered on the desktop – like the ability to search all opened cards at once or to filter all of them by the file type.
But the more complex the folder structure becomes, the more the benefits of File Cards grow. If you have many folders to watch (possibly on the microSD card, on the phone), it might become cumbersome to have them all opened, even with the zoomed out view that helps in managing of lot of cards. Enter 'workspaces', where you can remember any collection of cards as the workspace to quickly scan different areas of your life - like business document templates, several active projects, photos, etc.
Going back to Continuum, it is worth noting that File Cards is fully optimized for keyboard and mouse productivity with over 40 keyboard shortcuts. And it works just as well with touch (you can try that experience in the landscape mode on the phone or on the PC), and probably the most unique part is its productivity with a pen.
Some other features not supported by the phone's File explorer are: archive support, attaching reminders to files, creating new documents from templates, and changing of the file extension. File Cards is universal, so you can also have all the mentioned features on the PC where the opening of several windows with different workspaces makes for a pretty good experience.