I have to wonder if they just give us the illusion of being useful.
Just had an email asking if I could meet "tomorrow at 5:00 PM, or would 6:30 work better?". The suggestions were "I will be there at 6", "Tonight works" or "Either time works", only one of which is even valid! Maybe for every time it saves me a few seconds, there's at least one where I have to read them all and realize none fit before writing what I would have done without the quick replies.
That's actually a use case that I imagine could work well, if done well. Especially in fully integrated systems like GMail or our corporate Exchange, when the LLM can access enough data to produce meaningful suggestions.
IMHO the UX problem is, as the article points out in so many words, shoving AI slop down our collective throats as if we were geese waiting to be fattened.
Even "either time works" is only half-valid! If the other party has already declared their openness to either option, proper etiquette is to just select one so you can both move on with your lives.