They have terrible battery life. My first laptop I purchased in college was a top of the line Alienware. Never again will I do that. If you value portability and battery life at all I would reconsider. If you want power and discrete graphics get a desktop.
What's your point? "If you want power and discrete graphics get a desktop." is true about any notebook. Every notebook - except maybe those built from actual desktop hardware (which is mainly a configuration difference anyway) - will be far less powerful and more noisy than a desktop at the same price point.
Depending on the brand you'll always pay a 2-6 times premium for laptop hardware.
Re. battery life; it obviously depends a lot on the model. Some are quite okay, the gaming ones aren't.
My point is that I've personally experienced the pain of purchasing a "high-performance laptop."
It was incredibly heavy to where you unconsciously start deciding to leave it home because of the discomfort of lugging it around.
The battery life was so poor you have constant anxiety about when it will run out or if you will make it through your two classes.
The performance also ultimately wasn't that great and had terrible thermals.
I was left with a laptop that never left my desk. I would have been better off purchasing a cheap chromebook and a mid-range desktop for the same money. The "performance laptop" is compromise incarnate.