I, personally follow the advice of people who have actual real life experience with chinchillas. This includes ranchers, experienced breeders, and experienced pet owners.
Most vets do not have current information, and do not have a lot of experience with chinchillas. Most vets don't know the correct antibiotics to give, etc. They suggest fruits, veggies, nuts and such as treats.
Ranchers, Experienced breeders, and Pet owners live with these animals day in and day out. Many, especially the breeders and ranchers deal with day to day problems by themselves, without seeking a vet. (Fungus, simple wounds, breeding problems). They know how to deal with chinchillas, and know through years of experience and day to day dealings what is best for a chinchilla.
I do 95% of what I can at home. This includes fungus, breeding complications, and simple wounds that do not require stitches. My animals do just fine, and I know they are getting the correct care. Most vets i've seen and talked to *I* need to tell them what to do anyway, i'd rather just go ahead and do it.