It should be a mix of both. But by reading your response in other comments you are sticking to the definition of sde. But the definition says you develop software, (A software engineer is a person who applies the engineering design process to design, develop, test, maintain, and evaluate computer software)
In the design part, you also have to include business logic without which there's no software it's just CRUD. And nowhere in the definition is it mentioned that you have to solve challenging problems.
Regarding impact, I don't see why that's an issue, if you are doing something that has no impact then it's probably a hobby.
I am actually the exact opposite, I get bored if What I'm developing will not have any users? There should be a question as to what value your work has, if it doesn't you're just doing whiteboard masturbation and nothing else.