I'm dubious about the stated benefits, but as somebody with a severe specific learning difficulty which means I can barely write by hand but I have a fast and accurate typing speed it seems obvious that the brain treats them as different activities.
Great to hear about your ability to type fast and accurate – that's definitely a skill on its own.
About the benefits, you'll find a lot of information about eye–hand coordination / eye-hand-brain coordination. And it's benefits. But in the end, it's about the feel-good factor and what works for you
