This projects aim is to bring a range of linux distros to your android device through a method known as 'chroot', see it has running a linux distro within a virtual machine on your phone.
You can access this virtual machine and run it on your phone without causing any damage to your device, or having to overwrite anything.
Why might you want this?
well my apps are designed to make the install and set up process as easy as possible (more so in the paid apps) while still giving you some flexibility. Once you have the distro up and running then you can pretty much run and install any linux software you like (so long as there is a arm port or it is not architecturaly depenedent), sure there a very few big benefits over what android itself can do but it is still pretty dam cool. (and with the free ubuntu version, hey its free does it matter how useful you find it?)