As a woman who's had limited access to pockets for most of her life, why would anyone willingly choose to give up proper pants storage? Clearly, these men don't realize how privileged their existence has been.
Sometimes tight trousers have excellent pockets (menswear doesn't give a toss about pockets ruining the line of the clothing, even on skin tight clothing), like the man in the op photo with his phone deep in his right pocket
Yeah, losing pockets is a trade-off I don't always like. But some situations requires freedom of movement and the skintight pants are more aerodynamic. However I'm not into leggings, so jeans will do.