Yes, I've heard the arguments that you only use your iPad in an environment with available Wifi and in a worst case scenario can use your phone as an Wifi access point.
Well imagine this: I'm currently enjoying a winter vacation in Ruka, the north of Finland. We rented a nice cottage somewhere in the woods near a skiing area. Arround us we see snow, the sun, lots of trees and for the rest nothing. It's really quiet and a great place for a break from our normally very busy lives. The cottage comes fully equiped, including a sauna for further relaxation, but there is no Wifi.
When I travel I like to stay connected, this for several reasons. First and formost I use the internet for information, news and to stay up to date and this doesn't stop when traveling. I also want to stay in touch, because you never know which opportunities appear and there are several ways I could do this. I could for instance use the roaming facilities of my smart phone, but unfortunately the telecom operators see this as their big money maker and make this more expensive than necessary. Another alternative is that I regulary drive to the nearest village and use the Wifi over there. This works and I've done this before, but you do give up on being in the woods and the inspiring environment. The best option I discovered this year: Go to a telecom operator and get a cheap prepaid SIM card. Make sure to select an operator that also offers prepaid data on the SIM. Here in Finland you can get a great deal with local operator Saunalahti that offers 7 days of unlimited data for 6.90 Euro. The initial SIM costs you 6 Euro plus a 10 Euro recharge and you are in business. Well you are almost in business, because you first have to chop up the SIM card since no Micro SIM is offered in this deal. Put the SIM card in your iPad and it's working. Since this country invented GSM the reception in general is very good, at least good enough for me to write is post from a cottage in the woods.
Now of course you don't need an iPad for doing this. You could also put the SIM in our phone, but then you can't be reached on the phone number all your friends know. Alternatively you could use a USB stick modem and use the SIM for that, but remember your are here to relax and the iPad is less intrusive (and easier to carry) than a laptop.
An iPad, or other tablet, with 3G is the ideal travel computer.