Editor plugins are fantastic about completing based on a pattern. That's the main thing you're missing out on imo - it's worth it to hit tab, but not to copy/paste and say "finish this line for me, it looks almost like the one above."

There's also the real-time aspect where you can see that it's wrong via the virtual text, type a few characters, then it gets what you're doing and you can tab complete the rest of the line.

It's faster to converse with when you don't have to actually have a conversation, if that makes sense? The feedback loop is much shorter and doesn't require natural language, or nearly as much context switching.