(Image Credit: Courtesy of Asus)

There are so many questions about mobile device purchases these days: Do I need a tablet when my phone already does so much? Do I need a laptop if I can do so much on my tablet?

Today in Barcelona, at the annual Mobile World Congress trade show, Asus debuted an all-in-one answer to those questions - its PadFone. The 4.3-inch Android 4.0 smartphone comes with a tablet dock accessory that can transform the phone into a full-on tablet.

Asus has been previewing the device since June of last year, but it says it will finally be ready to ship in April. There's no word if it will be available in the United States; the phone would likely require a carrier and Asus doesn't have any U.S. carrier partnerships right now.

Asus is well-known in the laptop market, and has only recently started to branch out into the tablet market.

The phone is packed to the brim with new technology, including a dual-core Qualcomm processor, 8-megapixel camera with a Fuji image processor, and it has a high resolution qHD AMOLED display.

The PadFone Station - the tablet part - has a 10.1-inch screen and an extra battery that can keep both the phone and the screen powered on for up to 16 hours, Asus claims. When the phone is docked into the back of the tablet, you can navigate the phone's Android 4.0 operating system on the tablet.

                                                                                             (Image Credit: Courtesy of Asus)

But what about those who still want a keyboard? There's an add-on for that; a keyboard dock will be available for the PadFone Station to dock into. It will work a lot like Asus' Eee Pad Transformer or Transformer Prime, which are on shelves now.

Asus also announced a PadFone Stylus Headset - a digital pen for writing on the tablet that doubles as a Bluetooth headset for making and receiving calls when the phone is docked. Lots of double duty here.

It should be interesting to see how it works, and we look forward to a closer look in April, when we'll also find out what the whole package will cost.