If I were to see this moment, I would wonder how you can bear using a mouse when the keyboard is so much quicker. However, you can probably use the mouse much faster than I can.

Why? It's probably the power of habits. Using a keyboard-mouse combination to interact with the computer is how you've always worked. Using a screen reader with a large number of specialized keystrokes is how I've always worked.

I've had a tiny, tiny amount of experience with using NVDA through work and the first hurdle is the incredible number of keyboard shortcuts to learn. The only other tip I can give is to unplug your mouse and give it a go.

I do not, myself, know why this is the case. I can come up with several plausible reasons; for example, you're basically coming up with an alternate input device for your computer piggybacked onto something that's already there. Additionally these programs basically are the computer if you're blind; you develop a lot of experience with them quickly because the alternative is not using it at all. And some amount of it is probably cultural/historical, we make it hard because it's always been hard. Truly, I don't know, and I don't know anyone who does.