Colan, That's a good point of using CID of the GMB and using it in the embed code.
If my SAB client who can server 50+ miles from his place, then in this case I have to crate city based pages. That's where I'm trying to create the such kind of pages. Not sure, it will have a impact or not.
I'm mentioning the city name with schema markup, as each city page will have a dedicated schema markup with area served in miles.