That seems perfectly logical to me -- and it doesn't layer a psionics system onto a magic system. If I were going to make "magical" powers available in a SciFi setting, I hope I'd be clever enough to do it that way too.
It's always seemed to me that the primary difference between magic and psionics is one of semantics. In magic, I use mana to twist the forces of the universe to my will; in psionics, I use the discipline of my mind to twist the forces of the universe to my will; in effect, the same exact results, but a differing explanation of "how" it gets done. As far as the spells/powers go, they seem to be pretty much the same thing too.
Trying to force both systems into the same game always seemed like, oh, I don't know, an "apples and oranges" thing, if you know what I mean.
From: Marc Gacy <marcgacy@gmail.com>
To: tft@brainiac.com
Sent: Tuesday, October 18, 2016 1:30 PM
Subject: Re: D&D classic Psionics in TFT
I also remembered that years ago I made a Psionics system for Legends of Time and Space by Dark City Games. With a couple of exceptions, I primarily refactored all of the spells into eight psionic disciplines with seven levels to each, and you had to 'build' your knowledge in a discipline to get to greater powers. It just felt more like training your mind than the more scattered approach of acquiring spells.