If 1 in 10,000 people have a disease, then a "test" which always reports the patient doesn't have the disease will be correct 99.99% of the time. "99.99% accuracy" should be "looked at with skepticism" in that it doesn't tell you what you need to know to understand the quality of a a test for a rare disease (a classifier under conditions of severe class imbalance); at a minimum, you would want to understand it's false positive and false negative rate, not (just) it's overall error rate.

See example "A": https://en.wikipedia.org/wiki/Base_rate_fallacy