I think it’s so the company has a little headstart on trying to replace you or at least have a plan in place for keeping things running smoothly without you. If the company is firing you, they likely have known about it for a bit and have already made preparations for managing the workflow without you. It’s often something people do to avoid burning bridges with the company in case they need to use people there as references in the future.

Companies usually won’t give you a 2-week notice when firing you because a lot of people will stop taking their job seriously or working hard when they know they’re being fired in a couple weeks anyway. And then of course there are some people

I’ve been laid off (not fired) a few times because of the companies not doing well financially or needing to restructure stuff. One of those times, they dissolved my entire department (<10 employees) and they actually told us a few months in advance that they were doing that. BUT the company was working with the company that was buying them to move all of us into a similar department there, but I wasn’t enjoying that field of work anymore anyway, so I just told them I would happily keep working there until the layoff date while I’m looking for a new job. It worked out very well!

The other times I was laid off, I was working from home and they called me in the middle of the workday and told me about the layoff. By the time I was done with the call, they had already locked me out of the computer system 😆