Can you elaborate why? I saw most of the video on their website; it looked pretty similar to tmux (with different shortcut keys). Does it have any extra features? Perhaps out-of-the-box session saving even after rebooting?
A couple of obvious reasons: 1) it lowers the bar of entry into Tmux/Screen for newbies; 2) it has fairly intuitive mappings for newbies; 3) it is sanely configurable whilst not requiring the direct use of a dot file (just hit F9); 4) it may be faster to set up than Tmux/Screen (assuming you aren't able to copy a conf file for those); 5) it doesn't require understanding Ctrl-b/a for prefixing most commands.