Corn Cobs are inexpensive and effective, even if some regard them as inelegant. But how inelegant can they be if General Douglas MacArthur, Mark Twain, and Norman Rockwell all smoked them, right? As for effective, they have their place, and they have their value: for beginners, it helps that they are inexpensive, because you don't have to worry about ruining them, and also because you don't have to break them in the way you do with most briar pipes. More experienced smokers use them simply because they desire a cool, clean smoke. Others often wish to sample a wide variety of tobaccos and blends and so keep a stock of corncobs on hand. This lets them try new flavors without "carryover" from an already-used pipe, or it saves them from a potentially bad-tasting tobacco adding its flavor to a more expensive or favored pipe. So yes, corncob pipes = good pipes, with lots of uses - not least of which is - you guessed it - they smoke great.
On a historical note, the first and largest manufacturer of corncob pipes is Missouri Meerschaum, which has produced the pipes since 1869, and who - legend has it - invented them. Certainly they invented and patented the process of coating the bowls to make them durable, without sacrificing the coolness of the smoke.