I most certainly don't write faster than I type, and sending an email or a chat message certainly doesn't take longer than finding something to write with and something to write on. There is a big factor of habit and lifestyle - I don't usually write stuff down, so I don't have prepared/assigned tools for that, but I use my computer a lot, so I do have software installed and tools/commands memorised.
And, frankly, out of many possible options, plain text is something computers are really good at - there's basically no risk of running out of space, it's indexable and searchable, it's editable, and it's very universal.
Things do get a bit more complex when you include formatting, and a lot more complicated when you start adding annotations or illustrations, or even just more freeform writing styles, but there's still a major factor of habit - I don't know what my note taking would look like if I had a habit of pen and paper, but I know I'm very comfortable with using tech for that, and it works great for me!
That is kind of the issue - sure, there's janky workarounds, using an outdated version of proprietary software to try to block parts of the system from working when you don't want them to... But in the end, that's just one problem of many, so I kinda just never came back to windows after the incident. I just responsibly regularly update my system, and probably have a better experience and lose less time just updating manually.