How about using a cheap floating platform? One with a more efficient operating mode, larger payload capacity, less moving parts, safe failure modes...

Honestly the drone probably wins in all those categories today and the drone doesn't have the problem of needing to navigate choppy water, has a bird's eye view, and can't accidentally slam into the swimmer on a bad wave.

And you can buy them off the shelf, hell you can buy a drone right now today that can physically lift the person out of the ocean.

These exist and have been saving lives for at least 6 years: https://www.nationalgeographic.com/adventure/article/lifegua...

Costs 20x as much as this robot. It does have the advantage of being used successfully once.

The drone used in that situation is the "Little Ripper Lifesaver" which supposedly sells for around $50k[1].

From TFA, the cost for the boat was around $12k. That means this is about 4x more expensive, not 20x. That doesn't include the droppable inflatable boat but that is probably not going to break the bank either.

1: https://www.insidehook.com/culture/little-ripper-rescue-dron...