There's plenty of room for both. Many useful, worthwhile applications won't ever really push a machine to its limits, rather they primarily involve bringing structure and order to mounds of complex business logic. And that's OK. Not everything needs to be optimized.

On the other side of the same token, many useful, worthwhile applications will absolutely depend on this level of optimization. There are some problems which simply can't be solved in a practical manner without it. And that's OK too.