The phone with 4G will not be subjected to stupid corporate firewall rules preventing access to, say, StackOverflow.

Unless your phone was issued by your employer, is managed by MDM and runs all the traffic through your employers firewall anyway.

On the other hand, there are laptops, that have cellular radios. My old Thinkpad surely does.

Some exception cases: the phone needs to run a Mobile device management agent that installs and launches an antivirus, or the mobile happens to connect to a corporate VPN that routes all traffic and then inspects it via some appliance.

I'd just activate the hotspot on the phone to use the laptop.

I guess they like hiring more devs to do less work.