it would be kind of Maxwell Smart Agent 86 thing...lol. i use my iPad as a phone with the 3.5 earpiece or on speaker which works well. As for holding a Tablet/iPad type device to your ear, it would be and look a little award, even though the Galaxy fits pretty good in the hand.
For the most part these Pads/tabs aren't mobile enough to replace a phone, they're just too big for talking on-the-go the way a cell phone can. Cell Phones can be Hands free via Bluetooth/earpiece, but Tablets just don't give that type of mobility.
Pads are great for being somewhere and pulling them out for use, Pads might have the ability for earpieces and bluetooth communications, but their limited when it comes to on-the-go mobility.