Yes, you get the same version of deps and the actual software too. For example, wine breaks my game from time to time, but if I got clone my setup I will get the exact version of wine that I use that works, not the latest unstable version

No, it’s also for your system to use locked versions of deps, so if you git clone you get a flakes.lock as well with all the versions. When you install from a git repo you get the same system again

You can combine stable and unstable packages since they can have different dependencies

Given this you can have the base system be running the unstable versions, while holding back things like wine from upgrading