What do WordPress development services include?
Building the site is the small part. The work that decides whether it earns anything is what happens underneath: how fast it renders, how it holds up under load, how many plugins are quietly fighting each other, and whether it can be crawled properly.
So a build here covers the theme and templates, but also the render path, the database, the caching layer, image handling, and the security hardening that stops you rebuilding it again in a year.
The difference from most WordPress work is that the person choosing the plugins is the same one who has to make the site pass Core Web Vitals afterwards. That tends to change which plugins get chosen.

