For instance, native undo is time and word sensitive. I don't know its exact heuristics, but it always seems to do what you meant.
Gmail's Chrome and Electron, on the other hand, will often undo letter by letter or leave you in mid typed words, which is nuts.
If you want another example, I often write in multiple languages, something that's beautifully handled for you on native apps. Since Skype changed to Electron, it puts a red underline on every single non english word I type and there is nothing that can be done about it, besides changing the default system language and restarting the app.
There's also CoreText's sharp line width in retina displays no matter which background/foreground color combination you choose, built in dictionary a tap away, etc.
It's just a dreadful experience otherwise, once you get used.