Maru: a pocket desktop

Is it truly a USB to video output or is it taking advantage of the Slimport capability of that phone? Couple years back many phones had "one connector / two functions" where the USB port could be turned into a video hardware output. Google MHL or Slimport for details

May seem like a minor difference but it is huge in terms of power draw and processing load on the phone. Almost all phones support USB OTG these days but none that I know of support charging while in host mode (without custom ROM / Kernel). So if it depended on host mode, the battery draw would be totally impractical.