It doesn't have to be hot wallet / cold storage. Source code, business plans, revenue & profit statements, SSH to servers, physical access to datacentre, client contact lists, etc etc... there's a myriad things that are either valuable to the company or can cause harm to the company.
I've been escorted out of the building during a layoff once early in my career. Friendly, smiley, fake. It felt AWFUL. I'm as goody-two-shoes pacifist laid back easy going do-no-harm as it gets... and I definitely had various strong emotions going through my head heart and body at the time. So on both cold & rational, as well as personal & empathetic side, I understand both how the individuals feel as well as why companies need to do it.