We did, a temp solution, have 4 cameras at a site running over a LTE connection.
worked well no doubt, in fact here in Australia some of our cable connections for WAN are worse than mobile.
Obvious concern is the data usage, but we didnt have any issues on this front has only certain people had access to them and it was mostly inside the LAN anyway.
We did have an MX firewall with the LTE sim card in it that was handling the connection.