I think the easy data restore is actually a good feature here. The security concern with sideloading is the potential for social engineering. Having iOS display

I think the easy data restore is actually a good feature here. The security concern with sideloading is the potential for social engineering. Having iOS display a “Are you sure you want to enable sideloading? Doing this will delete all data on your iPhone.” sounds like it’d be a good deterrent to non-technical users. They’d be worried about deleting their pictures and chat history. More knowledgeable users would know about the data restore functionality and proceed after pulling any local-only data off their device.