Hi Miriam,
I added keywords to the business titles of Google My Business listings and I didn’t see any big ranking improvements on categories the business already appeared at.
I added keywords to the business titles of Google My Business listings and I saw a big improvement on categories the business didn’t already appeared on. So adding “SEO” in the business title of an webdevelopment firm could result in them being shown on keywords like “SEO The Hague”.
I Removed keywords from (compeditors) business titles and didn’t see a drop in their ranking visibility.
At this point I believe keywords in the business title could help Google associate your business with a keyword or service type but isn’t (or is only a small) rankingfactor. It’s the difference between being shown, or not being shown at all. Not the difference between position 2 and 3.
Note: I only tracked this with a few Google my business pages for a short period of time.
About the advice from the Google support staff, heard it the last time on 10 dec. 2015.