Based on past experience, I'd say Wix has already has a pretty hard time having an impact on local search rankings.
The integration sounds good insofar as it might help some of the less-savvy do-it-yourself business owners (who by definition are in the "more-savvy" pile, compared to people who don't even try). But I think for everyone else, and possibly even for people in the former group, it's another feature/option that will cause confusion. Lots of questions like, "I've got a GMB page - do I need Wix?" and "I'm on Wix - do I need GMB?" and "The Wix interface is showing me something crazy about my GMB page" and "Does using a Wix site help my 3-pack rankings," etc.
I don't get good vibes, but would be interested to see more.
