Power is real, that's a false statement you can say hp standard is kind of made up, it's very loosely based off what a horse can do, but that don't matter we don't use the number to compare what horses vs engines can do but what amount of work an engine can do. Power is real and we use hp as the measurement, you can use different types of power measurements if you like, but all convert to one another.
It like saying speed ain't real cause distance and time measurements are based of arbitrary units miles and hours.
Torque and rpm combined is what moves and accelerates your car but we need someway to rate that combined effort which is power and here we use hp to do that can use watts or some other power rating if you like.
I feel people don't quite grasp rpm is just important as torque. Eg.. Take an electric motor (flat tq curve) that makes, 500 lbs-ft from 0-6000 rpms, without a factoring the power at each of those rpms looks the the motor ability is equal across the rpms. But rpm multiplies the torques abilities, eg... About 19% every 1000 rpms, so @1000rpm hp is 19% of 500lbs-ft = 95hp, @2000rpm 38% of 500lbs-ft = 190 hp, @6000rpm hp is 114% of 500lbs-ft = 570 hp. So with out figuring out the motors power we'd be in the dark about calculating it's capabilities eg.. 0-60, et/mph, top speed etc.. Making it hard to match the required engine to the job.