I really doubt that our biological body can be better then artificial created robot bodies.
E.g. A body out of steel vs a body of flesh and blood.
Maybe you are talking about the moment but it will not stay like this in the future: I. E. Advances in soft robotics.
Your answer proves that you are one of these human robots. Nature is perfect in relation to sustainability. Machinery is never permanent. A killing machine needs a body out of steel, but after it has fulfilled his mission, it stops moving and begins to erode.
Human mankind can love, robots can not. If humans forget to love, they will starve to death.
Robots behave reasonable, humans do not. As soon as humans start believing to be reasonable, war is just around the corner.
1. Machine erodes
The human is a biological machine.
Everything except emotions and self consciousness can be applied to a machine. (Stand of today)
2. Emotions & self consciousness
Again, the human is just an very advanced biological machine (depending on scientists in development for 10 millions of years).
If we are advanced enough we will be able to create sentient machines.
3. Nature is in perfect sustainability
What about global killers?
Nature has a lot of random noises which is very logical if you believe in evolution.
You should read up more kneim to get up to date about science and philosophy.