He's 31 and hasn't played any type of professional football in his life. He's played some amateur, but not a great deal. It takes years to learn the skills required. It requires complete dedication and in his case, he dedicated his life to sprinting.
It's just not going to work. He's just going to take the spot of another kid that's dedicating his life to football and it's going to be a failure.
Even several big names are saying it's going to be a failure, Xavi being one of them.
It could work if, theoretically, a team puts 10 behind the ball and just plays route one football for him to chase. Finishing one on one with a keeper isn't difficult if you've got time to set yourself.
For the most part though I agree it's a waste of time and it's taking a spot from a kid, or hell, even a better suited marquee. Let Bolt play elsewhere and stop trying to bring the A League down to some circus level bullshit. It's bad enough as it is.