It's simply not realistic the 1000th time it's offered as the obvious solution.
If its not they should probably just work how everyone else works.
Except that whether it's better or not is probably contingent on the particular web site and particular user.
No, it's better for users who read the auto-filled boxes to make sure they are sane (which is what I do). It's not good for users that don't understand what auto-fill is (i.e. they think the website is suggesting it to them).
Easy to miss things.
Once those autofill, it's anyone's guess whether you have put the right data in.
Its super trivial to bind hotkeys to shell functions that operate on the current directory or files or whatever. I know that some of this can be done with custom actions but its nice to be able to a) bind keys not just provide a context menu item and b) create a custom command with a few clicks.
Example something like autojump or what have you is a common tool for shell users. Its nice to bind a key to pop up a prompt key in a string and have this jump to a directory in your file manager using the same source of info as autojump.
This took like 30 seconds to figure out and set up.
Another example a hotkey show a thumbnail gallery of every image recursively below current dir.