The de Novo 510K allows that a device does not have to be evaluated by the 510K and discovered NSE beforehand. This means that someone can submit a de Novo without submitting a 510K prior to it, if they find that their device can be categorized as Class I or Class II, and no marketed predicate device is present. With the de Novo, a person can ask for the FDA to classify the device. The de Novo process is useful in that it allows for companies to bring in their products at a better pace if there is only low risk. The main disadvantage of the process is making sure to understand the amount of risk the product might actually have. I feel that the de Novo 510K process is a good way to go with new products only if someone is sure there is a low risk factor and there is no predicate device.

References:
https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm273903.pdf