I've also run (and even participated in!) in academia.
In academia (at least the country I was in), it's very hard to move up a salary level. There's a lengthy internal, for higher levels even an external, review process with letters of support that have to be written, a panel that meets only every few months, etc. Going from academic level A to B can take six months. It's far faster to have your supervisor create a level B position hypertailored to you and have you apply, for me that took less than half the time. No letters of support, only one interview panel, you can finish all prerequisites in a few weeks.
Plus your supervisor gets to, as it's called in OP's article, 'talent-hoard'; there might be a good CV coming through for a future position.
In academia (at least the country I was in), it's very hard to move up a salary level. There's a lengthy internal, for higher levels even an external, review process with letters of support that have to be written, a panel that meets only every few months, etc. Going from academic level A to B can take six months. It's far faster to have your supervisor create a level B position hypertailored to you and have you apply, for me that took less than half the time. No letters of support, only one interview panel, you can finish all prerequisites in a few weeks.
Plus your supervisor gets to, as it's called in OP's article, 'talent-hoard'; there might be a good CV coming through for a future position.