A lot of people want a Mac because they have a nice form factor and they work in the Apple ecosystem. Macbooks were a bit expensive. It's obvious that an iPad masquerading as a Macbook was going to work, because a lot of people like a proper keyboard and don't need touchscreen. Macbook Neo fits a perfect niche.
I'm not surprised by its success, I'm just surprised that Apple are. I'm stunned their business case didn't imagine bigger volume. Why buy a more expensive Macbook for basic admin, web browsing, and streaming?