Not my idea, not my decision, but someone must have weighed the costs of laptop w/docks vs desktops and risk of one site going offline for a few weeks and decided it was worth it. For a finance company, I guess those days could carry a lot of cash flow if not regulatory risks as well which could help push the laptop argument.
I really liked the model laptops we were deploying and how the push allowed us to clear out some real old desktops. It was helpful to be mobile but I did keep an old desktop at my desk with tools and more that I could remote to from another desk or from home to do things on site.
A theft at the office, could result in dozens of computers going missing.
A theft a single employee's home, is likely limited to a very small amount of devices.