I only use the server part of Appium so, for me, the basic point of using Appium is for it act as a connection between my development/automation and a physical mobile device. I code my automated tests for the mobile app, which is an HTML hybrid app, in Java/Selenium. When the app is deployed to a typical server, accessible by a web browser, I dont need Appium because Selenium knows how to interact with my dev machine’s web browser. When I want to test the same app on an actual mobile device, Appium acts as a proxy web server between my Selenium and device so that the Selenium tests can still act like they are interacting with a browser and the device understands.
If you arent testing an app on an actual mobile device, there is no point in using Appium because that is really its only purpose… It is less a test development framework and more of a translation conduit for running test frameworks in an environment they were not built for.