I thought that I would never figure this out, but thanks to AppleInsider I finally understand.
Disadvantages of the 17″ MacBook Pro
Apart from being $300 more, the 17″ version is a pound heavier than the 15″ model and 1.1″ wider and 0.7″ deeper (it’s also a hair thicker). It won’t fit into sleeves for 15″ models, and won’t fit into a variety of bags or backpacks intended for “regular sized” laptops.
Once again, thanks AppleInsider for pointing out that 17-inch MacBook Pro is larger and heavier than its 15-inch counterpart. You know how much I hate having MacBook Pro with smaller screen to be bigger and heavier than the one with larger screen. What an observation! Without this information I’d be cursing the day while trying to fit the 17-inch MacBook Pro into a 15-inch MacBook Pro sleeve.