If it's a Silent Spinner you'd have a good idea of exactly why she doesn't use it,since in my opinion Silent Spinners are one of the worst on the market considering they rarely if ever work when you buy them and even if you get lucky and find a working one they don't stay working nor do they remain truly silent!
Luckily the Silent Runner is, to me, a functional,high quality,truly silent,and 100% safe(unlike any other wheel on the market,including Wodent Wheels and similar wheels)wheel that is available in a decent range of the world.It is online exclusive and is an investment,but considering the superior quality and how long they can last compared to any other wheel plus the peace of mind having complete safety that I feel investment is more than worth it.
I think the wheel that came with the cage is most likely dangerously small and would need removing
It is unfortunate,but I think it's much better to have no wheel temporarily than to have a dangerous wheel.