There are calls we could make to query storage availability, but we can't move forward at this particular point without loading the settings, so we need to wait.

We run on a limited number of devices, and know which manufacturers / devices have slow startups, so it's a little less resource intensive to just wait a few ms on those devices than to continually query storage, or handle the missing storage exceptions in a loop (invoking error handlers is generally pretty expensive, and we don't want to log this particular issue).

This is usually at a device reboot in the middle of the night when no one is working, so even a few seconds at startup isn't the end of the world.

Psychology. People think that if a process completes remarkably quickly, it didn't do the whole thing. Plenty of articles on the psychology of progress bars; take your pick.

One interesting scenario is that games used to have tips on their loading screens. With SSDs, everything loads so fast that if you might miss it if it closes automatically.