Some of you may be dissing Samsung on this ad but they do have a point, they brought the term Phablet to the market & made extra large smartphones popular, otherwise why would apple make a 5.5" iPhone.
I don't think the guy that first sold legal sized paper was making very much of an innovation beyond the guy that sold letter sized paper. "bigger" isn't much of an innovation unless you do something to make bigger work better in an unexpected way.
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You are obviously correct. But Apple announcing the product months before it's release is intended to create interest and hype, so IMO, it serves a similar purpose, although it's not bashing a competitors product.
I also suspect they would have waited if not for the fact that it was certainly going to leak soon, and they wanted to beat the leaks for once.