I agree with you. I absolutely love my Transformer Prime for the fact that I can charge it overnight and use it all day without having to recharge.
I spend perhaps 3-4 days a week in my car, visiting clients and attending trade shows etc. I never have to worry about the charge on my Prime. Does email, Citrix client, word processing, spreadsheets etc.
I also recently flew to China. On a budget airline that had no personal entertainment options, for over 10 hours. I watched several hours of TV shows during the flight. When I landed I still had more than 50% battery remaining. I stayed in several hotels with no Wifi. They had free internet over Ethernet only. A $6 USB-Ethernet adapter later and I was away. Moreover I was able to load photos from my camera directly onto the tablet through the full sized SD card slot and show them to clients/friends/family on the larger tablet screen.
At night I just left the keyboard dock in my luggage and just carried the tablet around. Visited a cafe or a bar, read a novel, surf on free WiFi. No recharging needed because during the day I had depleted the keyboard battery and not the tablet battery.
There are many reasons one would choose this form factor. I love it.