To get suckers to buy it.
You may have heard of the term "Searsucker"? Well, it means more than the material my grandmother used to dew dresses with.
Sears had a habit of advertising some theoretical momentary "peak" HP it imply to the unwitting eye that their saws were more powerful than the saws at Montgomery Wards at the other end of the mall. Ignore any HP sticker on the saw body, and only look at the nameplate on the motor itself for the real HP number.
In fact, I would ignore all HP numbers, and just compare amps. Be sure to make the amp comparison at an equivalent voltage. A 7 amp motor at 220v is more powerful than an 11 amp motor at 110v. The most versitile motors for small table saws are dual voltage, so that you can run at the more efficient 220v configuration where 220-240 single phase is available, and with a quick change in wiring run the same motor at 110v (albeit at near circuit breaking current levels) when and where 220v isn't available.