What is beneficial? Can we eat it or use it?
Beneficial is a subjective concept. We think rice is edible, so we think rice is beneficial. We think frogs can eat pests in the fields, so we think frogs are beneficial. Generally speaking, humans think that this kind of creature is useful to them, which is why they call it beneficial.
But does the world revolve around humans?
This is not the case.
We are afraid of snakes and think they are harmful because they are venomous. But the snake helped us eat the mice in the fields and protect the crops. It is also beneficial from this point of view.
But do mice, frogs, snakes, and even rice, cotton, and wheat really care about what is beneficial or not? No, maybe they don’t even have this notion of “beneficial”. They knowonly that if I don't catch insects to eat them, I will die of hunger and that if I don't have ears, my seeds will not germinate. They just want to survive and reproduce the species.
And that is the main theme of this world.
Imagine: if the frogs in this world disappeared, would humans still be discussing the usefulness of frogs?
It's gone, it no longer exists, and no matter how many comments you make, it's all in vain. So the frogs don't care, the snakes don't care, and the rice and cotton and wheat don't care either.
That is to say, human beings, creatures that are full of food, can only express their "useful" and "useless" opinions without any reason.
In the final analysis, the concept of “beneficial” is nothing more than a self-deceptive fantasy of human beings.
So do sea creatures, aquarists, care?