I agree with DeliciousDesserts, I think fondant would be too soft for a Cameo. I've only used edible icing sheets and edible wafer/rice paper in mine. And it grips those pretty tightly, so I can imagine it would tear fondant!
You do not need an edible printer, as without one you can still cut shapes - similar to, albeit more limited materials-wise, a Cricut.
However, I believe having an edible printer in addition to a Cameo opens up so many more possibilities.
For example if you do want to cut out an image (not just a shape) you will need to print it yourself from the silhouette software. This is where the print & cut feature comes in.
When you print your image from the software, the printer also prints readable 'crop-marks' on the edges of your icing sheet. When you put the printed icing sheet in the Cameo, the laser reads these crop marks so it knows where to cut.
You could not just put any preprinted image into a cameo and expect it to cut - it needs the crop-marks. Hope that makes sense.
In short, being an owner of both machines, if you just want to cut shapes from a wide variety of edible materials (fondant, gumpaste, cookie dough etc.) then a Cricut is the way to go.
If you want to print & cut edible images then I'd advise a Cameo + edible printer combo.
I made the butterflies on these cupcakes using my printer and Cameo.