Probably none.

The claims of better typing speed with Dvorak have never been demonstrated. Only Dvorak himself found a benefit.

It’s easy to change if you want and has been for decades now. Computers are flexible in that sense. But measuring productivity in words per minute isn’t much different than measuring it in lines of code.

QWERTY is not designed for speed but the exact opposite. And we are not monkeys typing randomly and continuously. We, as human beings, have valuable cognitive work, while typing is just a format conversion operation. Focusing there misses the point.

We should focus less on peak speed and more on sustained speed?

Not a dvorak user.

I infected myself with Colemak back in the days when I had time to mess around on such things, somewhat inspired by a programmer of acquaint, that suffered from RSI. I can say after 10+ years I've never suffered from RSI.

It's been a pain when trying to pair program but never really had any substantial regrets. I can't compare it to any previous era where I was a qwerty user as I learned to touchtype with Colemak.

I think anything that allows you to maintain typing speed (ergonomics) and reduces the chance of distraction from errors is worthwhile.

Does DVORAK somehow reduce the cognitive load of typing? Maybe I'm just a slow thinker, but I've never found myself in a situation where the rate limiting factor is the ability to physically move my fingers from one key to another. (On a real keyboard at least, tapping this comment out on a touchscreen phone I made several typos I had to correct.)