As a competent programmer I've already got an idea of what I'm about to write in my head, yet having an immediate prompt suggest a "do you mean this?" turns that train of thought away from what I'm writing and instead to "is the suggestion correct and what I want?" before accepting or ignoring it.
It's not for me, I just want to get my brain waves into the IDE as quickly as I can.
That said I can certainly see how it'd be useful when working with a language you're not super familiar with, perhaps one you just dabble in occasionally, or where you're learning programming in general, or a new language, where these hints could save you a quick search for "for loop syntax in $LANG".
It's very exciting to see what will come out of AI. There's a lot of stuff not relevant to me, but in time far smarter people than I will conjure up ways to make my life easier.