These features will auto correct simple spelling errors and offer suggestions to improve your grammar.
As the company notes in a recent blog post on the matter:
"If you're working against deadlines to write a lot of emails daily, correct spelling and grammar probably isn't top of the mind. These capabilities can also help you write and edit with more confidence if you're a non-native speaker."
Currently, the new system only supports English, but that's almost certain to change in the months ahead. Google plans to roll out the enhanced features beginning on August 20th for G Suite users who are on rapid-release domains. Anyone on a scheduled release domain will start seeing the new features on September 12th.
Here's a quick summary of what you can expect:
Google is undoubtedly correct that their changes will be most beneficial to harried office workers facing tight deadlines and non-native English speakers. However, there aren't many people who won't see at least some benefit from the new features.
These are good changes that will no doubt prompt other companies selling competing products to follow suit, which will slowly and steadily raise the bar. Kudos to Google for the coming developments. If you're anxious to try them out, you won't have long to wait.