You gain £ and ¬ with the extra key (and € with AltGr), although a few symbols are moved round: # and ~ end up easier to type, ¬ is kicked into the corner, and @ and " are switched compared to the US layout.
There is a Dutch keyboard layout that is similar to the German one, but the US-International layout is almost universally used in the Netherlands, and has been for as long as I recall (mid 80s). I've only seen a keyboard with the Dutch layout once (and I've seen a lot of old second-hand hardware over the years!)
So in the case of Python at least, I think it probably wasn't a consideration.
Most German programmers I know use US-International btw, but I don't know how common that is.
I know a lot of German programmers, as I am one myself and I work a fair amount in German companies, and I never knew a single one who used US-International (apart from myself in the brief phase described above).
It mostly works, I'm absolutely trained to expect qwerty, but my keyboard at home (G710+) tells my muscle memory to start typing with a German layout now. I've not had to use any clients' laptops for many years but I could see the problem, I have it when someone hands me a ThinkPad with German layout for example, but I'm willing to tolerate to type garbage once a month in exchange for being able to work with the layout I actually prefer.
My home computer is in the living room shared with my family, it still has a German layout, so I switch between US and German pretty often. I can type on both keyboards fluently. Somehow my brain knows that the computers have different keyboard layouts.
The only thing that still confuses me is a cheap backup keyboard that I have (when bluetooth doesn't work), which has a UK layout....
I can still type on a German layout, but only in German. I think the language change provides enough of a "context switch" for my brain.
The advantage is you get to keep both alt keys as alts. The downside is that you lose the Windows key, but I remap that to caps-lock.
Does anyone have experience with using stickers? Can anyone recommend a good product there? -- maybe that would help with the awkwardness of internal laptop keyboards.
But training my muscle memory that way turned out to be more of a pain than a gain.
As a freelancer, I'm frequently in a situation where I'm forced to use a laptop that a client has provided, with a German layout. Oftentimes I will not have an external keyboard on hand, like I'm in a meeting room and didn't want to bring one, or I'm on a plane or train.
In order to make that work, you'd need to be a pretty disciplined typist who doesn't rely on the labels on the keys at all so as not to be confused by them when they're in a different layout.
Back in those days, there were also many edge cases, like the login screen etc., where you couldn't customize your layout away from some default that the client has configured.
Also: Most of the pain comes from curly braces. So when you're doing Python & Nim you're mostly okay using a European layout. I also think it's probably not a coincidence that the people behind those languages are Europeans, Guido van Rossum and Andreas Rumpf.