Struggle is very good for learning, I remember as a child enjoying very difficult interfaces because I was proud of being able to navigate the software when I finally get there, becoming very efficient with it, and I learned way more about the domain. (I'm thinking for example Cubase, reason, Photoshop at the time, most linux softwares, vim,...)
While easy to use softwares are more 'enjoyable' and the dopamine reward is high for small actions, it also prevent to develop some ability and resilience in navigating harder things. When the software complexity increases, users get annoyed and don't use it correctly because they were never exposed to much complexity before. (thinking about medical softwares that require many many actions to encode a patient, finance softwares, etc..)
Now, not all softwares are made to improve one efficiency. In your case, the app allows a children to express its creativity in other ways, which is very valuable also. So I think it is good that the interface and the interaction are easy, the focus should be on the creativity and not on the manipulation.
Learning can and should be also through practice and raising the bar, I agree, but don't mix learning as a general concept applied to a population with your own survivorship bias.
I think both kind of applications should exist in parallel. I generally dislike current trend in professional softwares that try to be easy to use, at the cost of less power or more clicks to do a simple action.
Professional apps should stay professional and more time should be spent in training power users.
I'm trying not to mix with my own survivorship bias,but I tend to believe that current trends of design remove the existance of advanced users at a young age. The applications are so polished and limiting that you don't spend time trying to do complex things with them.
I find bugs in old apps were a feature for learning. If it doesn't work, you try to understand why. Curiosity is intrinsic to young children, until we remove it by giving them something that never bug or limits their possibilities.
While easy to use softwares are more 'enjoyable' and the dopamine reward is high for small actions, it also prevent to develop some ability and resilience in navigating harder things. When the software complexity increases, users get annoyed and don't use it correctly because they were never exposed to much complexity before. (thinking about medical softwares that require many many actions to encode a patient, finance softwares, etc..)
Now, not all softwares are made to improve one efficiency. In your case, the app allows a children to express its creativity in other ways, which is very valuable also. So I think it is good that the interface and the interaction are easy, the focus should be on the creativity and not on the manipulation.