I'm a sucker for crank radios, and I own a couple of them. I don't own one that will readily charge other devices, but if I found one at a good price, I'd probably get one. After all, I am a sucker for them.
But as a practical item, I have my doubts. First of all, on the two I own, the cranks look a little bit on the flimsy side, particularly the fold-out plastic handle. Eventually, it's going to break. The actual generator mechamism is probably more robust (although I don't know that for sure). But if the handle is broken, it's not going to be much fun to operate. And I have no evidence to back me up, but I strongly suspect that the mean time to failure of that handle would be the equivalent of a couple extra set of alkaline batteries.
In other words, these radios exist because people realize that batteries won't last forever. But the plastic crank won't last forever, either. So at a minimum, if you plan to rely on something like this, you should make sure that it's built in a durable fashion. But I suspect that a box of alkalines would last longer.
As others have noted, it does take a lot of cranking. Both of my radios also contain a flashlight. It's better than nothing, but it really only functions while cranking. The light will quickly drain whatever charge you got from several minutes of vigorous cranking, in a matter of seconds. The radio will actually play for a reasonable amount of time. I forget exactly, but it's something like 10 minutes of cranking will give you 5 minutes of uninterrupted listening. (In that sense, these are a good emergency radio for people who are forgetful about keeping batteries on hand.) I've suspected what the last two posters have discovered--it will take a lot of cranking to give a reasonable charge to an external battery.
Since most people own a perfectly good source of 12 volt electricity (namely, their car), I think having a 12-volt charger is infinitely more practical for 99% of people's needs. The other alternative, of course, is those spare alkalines. Especially in the case of a cel phone, that's probably the best option. If it's a situation where you are unable to buy batteries after you've used up the last of your one month supply, then the phone probably isn't much use anyway.
For modest electrical needs in a TEOTWAWKI situation, then a solar charger is probably the best bet. I have an inexpensive one that will fully charge two AA cells during the course of one sunny day. That's probably enough to keep a small radio operating more or less indefinitely, with enough juice left over to use a flashlight for a few minutes each night. For slightly larger needs, then a small 12 volt panel would be the next step up. We have a very small panel (I forget the exact size, but it's something like 5 watts), which is enough to keep our camper battery charged more or less indefinitely for very modest use of lights and water pump.