I'd love to get an omni plant as a gift! just the seed would go nicely. You get the seeds as a reward for completeing a gardening challenge which does not seem to be coming up for my current sim.
You can feed the omni plant with a wide variety of items from your inventory. It will then reproduce that item several times. So, if you feed it perfect deathfish, it will produce several more perfect deathfish. Or, use it to make money by feeding it a very expensive book.
Or, with one plant you can rotate the feed items to maintain your stock of fish and harvestables without having to grow a lot of individual plants.