I’m not saying that we should let bees or sheep or any important animals that benefit humans and the ecosystem. But why the hell do we need to maintain wild animals such as tigers and dolphins if they don’t provide food or material for engineering. Seriously why do we need to save some obscure endangered animal if the species itself is deadly too, which is a problem for humans and livestock. It’s okay if the species dies out, we don’t need to make a big fuss about some fuckass animal going extinct. It’s a part of nature and history, nothing will remain the same for centuries.
All animals play some part in the ecosystem, however small we may think it may be. The previous comments go into more detail, but the thing is that every part of the ecosystem can be seen as a contradiction, be it an antagonistic one or not, in the case of symbiosis. I urge you to think about the place of these “unimportant animals” in the ecosystem, as your observations seem very unmaterialist.