IMO, the biggest problem with auto feeding live food is that you need to keep the enrichment value up. To do so means having the enrichment in with the live food until the live food goes to the tank. Unfortunately, the enrichment then goes to the tank as well.
Now if someone comes up with a system that sends the live food to a sieve, with the enriched water going to waste, and then turns the sieve over and washes the live food into the tank, we will have something good.
Then the next hurdle will be to also have something to add enrichment to the live food as needed, so one can go away on holidays.
With seahorses, I certainly don't want any enrichment in the tank, nor would I with my reef tanks.
As for a brine shrimp hatchery, I would NEVER want hatching water to come in contact with any tank water, even if the cysts have been decapped.