Maybe they're all secretly traps. You can't change back from being a dragon; if you choose flight, you just start floating upwards and can't come down; you're not immune to your own poison breath; courage just makes you incredibly over-confident in your own abilities...
Oh I didn't think of that, yeah I think in that case I'd rather be stuck as a dragon, even if I can't turn back. Way less risky/dangerous than not being able to control the others. Would require adjustments and adaptations but hey, still better than having to chain yourself down so you don't float away.