I always thought that was really dumb. After hearing stories from people then "find a skill in demand that sounds like a fun challenge" is a way better approach. I went for software but mech/civil engineering, carpentry, electrician and architect would all also be great choices.
Yeah, finding a career that is acceptable and pays enough to afford the lifestyle you crave is a balance. Usually that advice comes from people who love doing something that is coincidentally also highly paid.
Also, loving something and being actually good enough at it to make a career out of it are also two different things
Depends what part of the process you like. Some people like to be very meticulous in their hobbies, and somewhat of a perfectionist. That rarely exists in a professional environment, where everything is based on getting projects out the door, on schedule and on budget.
I actually like banging out projects quickly, so the professional life of my hobby suits me well (woodworking). I love pounding out big mortises with a sledgehammer, planing big boards and watch chips go flying. I hate fiddling with joinery and slowly fitting them for 10 minutes (slowly learning how to do them faster). For other people, joinery is their favorite part.