Let me understand what you said. Our immune system is not great and it is kind of weird to think that our own natural immunity is not as good as a rushed and useless vaccine? You have to be forgetting your sarcasm tag...
Okay, ready for a long and detailed explanation of immune system function?
We are born without adequate immune systems. Our immune systems develop throughout childhood and, according to a veterinarian friend of mine, reach maximal development around age 18. The immune systems of young adults have peak function, although in some cases, this leads to potentially deadly cytokine storm. As we age, our immune systems stop working so well. Around age 65, immune system function begins to decline significantly, so that you are less able to fight off infectious disease.
In addition to age-related changes in immune function, some people are born with a genetic variant of the immune system that prevents them from adequately forming an immune response. Others get a disease like cancer that impairs immune function. Or they get an organ transplant and receive immune-suppressing drugs.
So, no, our immune systems are not perfect and some don't even work well or at all.
"Natural" immunity, by which I presume you mean "disease-induced immunity" is not as good as vaccine immunity. This is because the virus contains 29 different proteins as well as the mRNAs and RNA genome to code for those proteins. Your immune system can easily choose the wrong proteins to make antibodies against. Antibodies against a protein that is located on the inside of the virus where it is protected from antibodies do nothing to block the virus. Only antibodies that attack the spike protein on the surface of the virus are capable of physically blocking the virus from attaching to the ACE2 receptor. Their attachment to the outside of the virus also signals the immune system that there is an invader that needs to be destroyed.
The mRNA vaccine technology has been in development since the early 1990s. How is a technology that has thirty years of development behind it "rushed"? And how do you scientifically characterize a vaccine that specifically targets the protein that the virus needs to initiate an infection as "useless"?