Not having to paste is very useful. Especially on mobile where pasting is slow and tedious. A few months ago I would have said the same thing as you, but then

Not having to paste is very useful. Especially on mobile where pasting is slow and tedious. A few months ago I would have said the same thing as you, but then I experienced some applications which looked at what I had copied and automatically did all the hard work. It's a pleasant surprise to see it happen, and having experienced it, I am happy that the applications have this functionality. Of course if you're living in a world where all the code on your device is considered hostile, then you may not want this. But I use almost only free software and there you can generally start with a presumption of goodwill instead of starting with a feeling of distrust, like with TikTok.