I sometimes trust 3G (and now 4G) more than I trust the available wifi, even over a VPN. Admittedly it's not that hard to put up a fake base station, but it's basically unlikely. Sometimes wifi at events is just badly run or overloaded, too.
There are also sites with rules about what's allowed to be on the network or not. Often a consultant or guest can't put his device on the network, at least without a lot of work (BYOD isn't done on many networks), but having network access is useful. There are also sometimes IP considerations (using an iPad or 4G hotspot during a break from a day job is less likely to be "using employer resources" to manage your startup if you're moonlighting than if you use their wifi...).
For +$130, it's worth it to me to have the capability. It also makes GPS more accurate, and maps is a really cool thing. I only replace my iPad every second generation, though.
There are also sites with rules about what's allowed to be on the network or not. Often a consultant or guest can't put his device on the network, at least without a lot of work (BYOD isn't done on many networks), but having network access is useful. There are also sometimes IP considerations (using an iPad or 4G hotspot during a break from a day job is less likely to be "using employer resources" to manage your startup if you're moonlighting than if you use their wifi...).
For +$130, it's worth it to me to have the capability. It also makes GPS more accurate, and maps is a really cool thing. I only replace my iPad every second generation, though.