Except in this case, some of us actually are. I will end up with more data across my three lines, more (unlimited) minutes of talk time, and the same on texts(unlimited), for less money. If you have a very recent plan, depending on how many phones you have, the type, and your usage, this can very well save you money.
Of course you were limited to begin with. My wife is planning on getting an iPhone when her upgrade comes up in the middle of July. I guess I can kiss my unlimited plan goodbye, unless I buy her a used phone. Grrr....