It's reverse engineering...
The stories are made up to support religions. If there is no inherited sin, if there is no such thing as perfection, there would be nothing for 'God', or 'Satan', to do, and we wouldn't owe anybody anything.
Any purpose religion gives to life is from its own perspective. It has nothing to do with deductive logic or reason, nothing to do with reality, only with belief and faith.
The big difference between science and religion is that science is universal; religion is not. The same with the "logic" religion uses: the prerequisite is you must accept the religion using such logic. Scientific facts can be accepted by people of any religion.
Just some thoughts...
S