Hello, I would recommend you to check out our documentation here:
https://docs.kentico.com/k10/developing-websites/developing-sites-using-asp-net-mvc
If you are following the officially supported setup, Web farms are crucial as you need synchronization mechanism between your MVC application and Kentico (both use same db but they somehow need to be notified that the other app made changes to it which is crucial for Smart Search functionality)