If you're using the proprietary drivers: Absolutely nothing will change for you.

If you're using the Nouveau/NVK drivers: Soon the OpenGL driver will be entirely replaced by Zink, which implements OpenGL over Vulkan (think DXVK, but for OpenGL); as the aforementioned driver is in a quite broken state, and nothing short of a complete rewrite can "revive" it.

Sooo... if you're already able to use NVK, you'll keep using NVK, but this time you can utilise it for OpenGL applications as well.

Basically, it means recent Nvidia GPUs will become viable using open drivers sooner, since developers won't need to update/port the older open OGL driver, and can instead just use Zink (OGL -> Vulkan wrapper). OGL support itself is important because accelerated compositors (like those that use Wayland such as recent Gnome/KDE etc) and older games native games rely on it, as well as many other pieces of a typical Linux desktop.

In the long run, competitive open drivers will mean greater longevity for these cards. There are AMD cards that are pushing 15+ years that are still usable today because they have open drivers.

Approximately not at all. They're changing the way they implement OpenGL for those cards, which will make their development and maintenance work simpler.

it means once all of this is added to the desktop OS you use, it will be plug and play for Nvidia GPU's.