So I don't have to spend 10-15 minutes saving all my open files (including the scratchpad ones I haven't named) and then later reopening all my applications, recreating all of my tmux windows and panes, setting up my vim splits and tabs again, and starting all of my stopped Docker containers?

Now that I have an nvme SSD in all my computers and boot times are roughly 10-15 seconds or so unless something has gone wrong, the advantage of sleeping is somewhat mitigated.

Back in the spinning rust era, though, a good unsuspend could be something like 50 times faster to get to a running computer. Possibly more, depending on what your OS needed to start up.

It is still more convenient to have my previous environment most of the time, and still faster to unsuspend than boot, but it isn't as much of an advantage as it used to be, no.

It takes ages to cold boot. My desktop is ok-ish, but it doens't matter since I only use it occasionally.

My old HP laptop had a slow-ass BIOS that I was convinced had some kind of bug. I replaced it with a brand spanking new thinkpad 2-3 months ago. Guess what? The freaking BIOS is EVEN SLOWER somehow!

They all wake up instantly from sleep.

I therefore only shut them down when I know they'll be unplugged for a while, because for some reason the HP eats through the battery even when off. If suspended, the battery will be out of juice in like two days. Haven't tried any of this with the Lenovo yet.

Suspend used to work great, but since MS figured they should copy Apple half-assedly, suspend is borken. And I have really no idea what we've gained in exchange.

If you turn it off, it might attempt a 45 minute update when you start it again (yes this has happened to me with macos).

The same reason that you don't do a full shutdown every time you walk away from your computer. I don't really believe that you don't understand this.