Kalos - trees don't produce fruit to do good for its own sake. It may seem that way but it is actually a seed-dispersal strategy.
Other plants encase their seeds in burrs that attach to animals and are dispersed that way. Other plants employ dispersal by wind.
Lower plants such as mosses and liverworts have motile sperm! It's about methods of reproduction - the passing on of genetic material.
If you choose to see 'God' in all this, fine. But expect your opinions to be challenged on a public forum.