I don't think iOS is "taking aim" at macOS. But a lot of people do use the iPad as a primary computing device these days, and the new iPad features in iOS 11 are definitely aimed at making the device even better for these people. For the things an iPad can do, it should do them as best it possibly can. For the things an iPad can't do, or can't do well, there's always macOS. And making the iPad better at the things it can do well doesn't harm macOS in any way.