Useless. Get the cooking zone off of the island.

See ceiling collection related comments in https://www.houzz.com/discussions/5912714/recessed-ceiling-hood-vs-telescoping-downdraft#n=14 for the most recent of several threads related to this topic over the past 10 years.

One way of looking at this is to:

• understand the primary functions of cooking ventilation
• understand that commercial hoods (and sometimes expansive ceiling extractors) are the way they are to optimize performance in achieving those functions
• understand the compromises residential hoods make to incorporate cost and aesthetics considerations
• understand one's own preferences among the compromises

Then evaluate quantitatively the performance factors needed that a given configuration must have for the cooking envisioned. Many threads here delve into these aspects.