Absolutely, it is necessary. It is essential, in the most obligatory manner.
Have you ever wondered why, for example, the leading scientists and academics of our country, including top doctors of science, collectively write appeals? They sign petitions, address the authorities, and ask to stop certain dangerous legislative projects. These are the minds of our country who know exactly why and what they are doing.
Or why do some groups within the system actively try to limit people's ability to express their opinions, leave comments, and especially speak out against environmental issues?
Because everyone understands that the only force capable of changing everything is society. That is why you are convinced that "it's all useless, don't even try to say or do anything."
If it weren't for you, all the projects would have been approved long ago, they would have torn apart the wilderness without a second thought. But at least, even in such difficult times, society manages to restrain the destruction of nature.
The fact is that the system of government is not homogeneous. While many pursue purely personal interests, many also try to change things, want changes, see problems, and care about nature. Without public resonance, without numerous requests from the grassroots, these people would have nothing to operate with within the system to solve problems.
Moreover, appeals are still recorded, even if you receive another formal response. The scale of public dissatisfaction is visible and quite tangible to the authorities.
Even formal responses are needed by society because they are literally a recorded evidence base that shows both the incompetence of some "responsible persons" and the general nature of deep systemic problems. It is a chronicle of direct evidence! It is important to preserve every formal response, to combine and systematize the data.