I think it's a case of good marketing and good packaging. Realistically you need a laptop to do serious field stuff with a flipper, but only if you plan on doing any testing and reconfiguration and only initially. The flipper isn't much bigger than the limesdr card, but it's nicely packaged and portable so once you have it ready to go you can throw it in a pocket.

The community also helps. The flipper is wildly overpriced for being a glorified happy meal toy but millions of people squeezing every ounce of functional potential out of a happy meal toy is better than a few dozen people writing academic papers with mostly high end industrial (cellular base station) and military applications.

And it has a fun dolphin mascot!