When Gmail introduced smart replies in the message editor, I was skeptical. The suggestions seemed simplistic, too concise, or vague.
With increased usage, the suggestions became slightly more relevant. And Gmail added smart compose, a more extensive text auto-completion feature. That makes a difference as the suggestions are actually helpful and save time. For example, they often spare me from manually inserting salutations, or fairly elaborate sentence fragments. Along with grammar checking and email templates, these message composition tools concretely improve productivity and text quality.
Learn in this issue how to use these Gmail features. Worth a try.