I can type "I" and then my phone's keyboard will suggest "be there at" as the phrase completion it does this a single word at a time, but in practice it does let me complete a phrase. If I don't want to say that, I'm capable of not using the autocomplete suggestions. There's no substantive difference with Smart Compose except that I don't have to confirm between every word, so its slightly more efficient.

I'm not sure what you think smart compose is doing, but "writing sentences for you" isn't it.[1] So no, I think you're either misunderstanding what this is, or perhaps you're being disingenuous by describing it as something that writes sentences for you.

[1]: Granted given the Duplex demo and other work in the NLP space, I expect that in certain contexts a tool that given an instruction like "set up a meeting with John this week" that schedules it over emails (like x.ai[2], which has been around for quite some time) is totally possible, but Smart Compose isn't it.

[2]: https://x.ai/

But for otherwise mechanical things ("hey can we set up a meeting tomorrow", "do you want to grab lunch at ____ today"), the form is mostly irrelevant. It's the kind of thing where if we weren't in a formal context, I'd write as "hey u wanna grab fud at ____ later". I'm not losing anything by having a tool formalize that to "Hey do you want to eat lunch at ____ today." Again, we already do that a lot. As far as I can tell, this is just doing that a bit faster.