In a genuine and everyday real sense, no, your likely thousand dollar device is not usable. The App Store requires an account to download from. Internal services and apps often complain about not being available. You are mostly stuck with whatever built in, non-cloud services the device comes with, which isn't much. Weather and mail fetching come to mind. Maybe some of the simple recording / note taking like apps. A working Apple ID is essentially a requirement to actually use the device you purchase. And yes there will be comments from folks about "ways" you can perhaps sideload or get things running, but to a regular person that simply uses a phone like a standard appliance in their life - they're stuck.