Isn't a better analogy the new crossover cars? People want the space of an SUV but don't like riding high or want to save money on gas... It doesn't handle as good as a sedan nor it can handle the rough tasks that an SUV can but there's a market for them.
In bikes there's people who want some of the features of a road bike and some of the features of a mountain bike but don't need the more extreme features of each design.
I finally settled on the Cannondale Quick 3. The gear ratios of the Quick 3 are more suited to the type of riding that I'll be doing than those on the Quick 2. I've also read that mountain bike gear ratios are better suited for beginners for when going up hills and there are quite a few hills here that it may come in handy. I guess that If I ever need the gear ratios of the Quick 2, I'd be better off with a true road bike which I may or may not decide to buy in the future.