Coders often like their craft, they like creating things, even if the final product is not important to them on a personal level.
Most software engineers rarely need to come up with new data structures or fancy algorithms. Most of these things are already there, we just need to know which ones to pick in a particular situation and how to glue them together.
Creating new algorithms or data structures may be scientifically creative. I don't know, maybe it's boring for the scientists and they think reasoning and writing about these is much more fun and creative than implementing them. Anyways it just one kind of creativity.
But there is creativity in 'just gluing' stuff together. It's not that simple and there is more choice involved than you suggest.