See scrollaway's response above. A lot of the text you already read is robot-generated. More than half the words in this comment were generated via autocorrect or auto complete in some fashion. It's still useful and thoughtful though.
Just to be clear, I don't find these things reassuring, it just makes me think you don't care about communicating very much. Please accept that some people find machine-generated communication to be gross and don't want to be subjected to it, whether or not you understand.
Saying you don't want to be subjected to machine generated communication to me says that you don't want to read anything written in the past 10 or so years. Practically everything written in that time frame is in some way machine generated or edited.
Like I said, just because something is in part machine generated doesn't make it not thoughtful.
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/
I think this is a dangerously stupid way to think about linguistics.
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.