Yoast Local SEO adds schema, maps and a store finder. GMB To Pages plans and drafts each location's service and city pages, and holds back any that read alike.
A page with an address, hours and a map tells Google a location exists. It rarely wins the search for the job a customer needs done in that town. Multi-location operators who post for help ask for service and city pages, one set per location, and they ask for pages that are not the same template with the city name swapped. GMB To Pages builds that plan from the Business Profile details you paste in. Each location gets its own service pages and service area pages as drafts, and any page under the 75 percent uniqueness bar is held back with the reason.
Yoast Local SEO does things GMB To Pages does not: location schema, a geo sitemap, maps, opening hours and a store finder. If your customers come to a branch, you want those, and the two plugins can run on the same site. GMB To Pages is for the pages that win the service search in each town, which Yoast Local SEO does not describe writing.