Why do I need another device?

Maybe I'm missing something here. 

I have my smart phone, my kindle, my netbook (which I strongly suggest you do not ever even think about buying), my  laptop, my desktop... why in the world do I need a tablet? 

Thanks to all of this technology : 

• I can get email everywhere - it can be back-lit, sideways, big, small, or only partially visible due to screen limitations. 
  
• I can make phone calls from any device. I can call from my desktop, my phone, my laptop... The kindle can't be used as a phone yet but I bet it will do that too. 
• I can get books from Google or Amazon on my phone, netbook, desktop, kindle... 
• I have built- in cameras on every device except my desktop. 
• I can play Angry Birds on any of these devices - well except the kindle, but I can get Halloween Mahjong on that. 
• I can easily attach almost all of these devices to a projector. Tablets require special converters for this purpose and from what I have observed with my Ipad-loving friends, they require access to a technical support person to make it all work. 

Depending on how you look at it, the tablet is either a very nice replacement for a  pad of paper, an electronic photo album, or a flattened double-sided camera.

If I can't use it to show my presentations, it is going to be hard to find enough value in adding another (however cool looking) device to my rolling bag of "portable tools" plus the myriad plugs, keyboards, mice, extensions cords, screen cleaners, covers, and styluses that are needed to make them all work. Sigh.