So I've had my chinchilla for about 8 months now, and I can tell you from my experience, they're very smart, and very picky. I used to buy these treats, so here're the facts:
-The GOOD-
My Chinchilla loved these things, they were his favorite treat, and that would make these great for training, i.e., training your chinchilla to come to his cage after out-of-cage play time, BUT...
-The BAD-
The first thing you should know about chins is that when you want to try a new treat with them, understand that they don't usually like to try new things. Sometimes it takes time, and repeat offerings, and sometimes they'll try it and usually they'll like it IF the try it.
These things are loaded with sugar, it's the first listed ingredient, and if you actually taste one of these, you can tell.
That's the thing, Chins are very susceptible to obesity and diabetes, so giving them too many of these types of sugary treats can be harmful. If you only give one a day, it's probably not too harmful, but as a Chinchilla owner, I would say it's best to give half a day, unless you give the treats infrequently, then one is probably totally safe :)