Wel, if they were just little throw away things, I don't know why she would mention them, but that's beside the point I suppose.

Time turners give an immense amount of power to anyone who has one. People could wreak havoc with them, and i would be realistic to expect that serious damage has been caused by them, but we don't hear about any of the damage that they have caused. This is problematic from a storytelling standpoint because as a reader I don't buy it. It's a device that worked great for PoA, but it has these problems which is why I think she decided to destroy them in Order of the Phoenix. It was a way of not having to potentially deal with any of these issues.