Having a huge tank is being able to keep absorbing punishment and keep going at a reasonably high level.If we’re still talking about Sharp then it’s not just that he can run fast, he’s won every long distance time trial since he’s been at the club and by pretty significant margins. If he didn’t have the tank he has he would’ve struggled to get drafted in the first place, it’s his number one strength by far imo.
Running fast either sprinting or over 5k or whatever is being able to run.
It doesn't mean you can play footy ,win the ball ,stop your opponent winning the ball or whatever else.
I'm genuinely surprised because someone is a brilliant runner anyone thinks that necessarily means you have the tank to keep going in a game of footy.
Of course it helps if you can do the essentials well.