Who the heck wants another cellular package for a tablet? With literally two keystrokes I can connect it to the internet using my smartphone as a hotspot, if needed.
I've made the same argument a couple of times, but recognize it WAS more of an issue before 4G since you couldn't use the hotspot and talk on the phone at the same time. The dynamic has changed slightly with the Verizon share plan that lets you add a tablet for only $10 per month. It might actually be worth that for the direct access capability.
I currently use the hotspot and like it. You also have the advantage of not obsoleting your tablet with cell technology upgrades. My Nexus was used on 3G, then got a bump to 4G when I upgraded phones. I suspect it will get used on 5G whenever that becomes a reality.