I'm confused. If you get a 4G tablet, you can also the sign up for the feature to allows it to turn into hot spot (assuming it even has this feature.) Do you mean 4G or Wi-Fi only tablet?
If you're connecting the tablet to a hotspot you're still using the 4G network. The only benefit of having a tablet with 4G is that it can connect to the Verizon towers on it's own without connecting to a hotspot first. However that will mean paying $10 a month to have a tablet on your account. To me that feature is not worth $120 a year. Just get a wi-fi only tablet. connect to wi-fi whenever you can and if you need to connect to Verizon's network you can always turn your phone into a hotspot and connect that way. And there's no $10 monthly device fee.