Eh, we’ve had our self-hosted Github go down for a couple hours in the daytime, and it wasn’t a big deal. We have something like 60 engineers spread out across the globe, about 15-20 that were directly impacted by the outage (the rest were in different timezones). Yeah, it was annoying, but each engineer only creates like 1 or 2 PRs in a given day, so they posted their PRs after the outage was resolved while working on something else. Yeah, PRs were delayed by a couple hours, but the actual flow of work didn’t change, we just had more stuff get posted all at once after the problems resolved.
In fact, Github would have to be out for 2 days straight before we start actually impacting delivery. An hour or two here and there really isn’t an issue, especially if the team has advance notice (most of the hit to productivity is everyone trying to troubleshoot at the same time (is it my VPN? Did wifi die? Etc).