What? I've never worked for a company that would tolerate downtime during deployments. Downtime is ok for personal projects, but not for most business applications.
Even for online business some downtime might be acceptable or even preferred. I used to work for a company that made most of it's money through a website and it would take the site offline for 8 hours a few weeks before important events to run a full scale load test on the production infrastructure.
Another place I worked we had to schedule downtime even when updating applications that were designed for zero downtime.
I have never worked a place that didn't allow for downtime or even heard of such a place other than the big tech companies.
Not only is that a pain for whoever is monitoring the deployment, but now if the deployment breaks something you're going to have to go wake up all of the relevant stakeholders, if you even know who they are.
Not to say late night deployments are never justified, but definitely not something devs want to be doing regularly.