It's kind of like going in and using a terminal instead of a somewhat-training-wheelsy and less powerful GUI, but not actually knowing thoroughly how to use the terminal. Maybe, I don't know. I'm not great with text based user interfaces but I know it's easy to screw stuff up if you're to ambitious.
The artificial methods that chemists have of doing things that nature does... doing the work of enzymes and such with high heats, acids or bases, and toxic metals... are just not as well suited. They're clunky, imprecise, time consuming, and easily give you results that you certainly were not looking for. What nature is capable of doing with strings of amino acids is fairly roundabout and Rube-Goldberg-esque, but also takes place under amazingly gentle conditions and, more interestingly, is amazingly precise.
What's more, nature builds these things exactly how they're meant to be built without unintentionally screwing up things it didn't know was there. Obviously we have a long way to go in that department, and we should probably do a bit more poking around before we start blindly bulling around in things we don't understand.