I mainly see the ViewComponents as a different way to render "partials". There are a lot of other things that come along with this (organization of code, testability, isolation, etc.) but at the end of the day, it's still views that we are rendering. With Turbo Frames, we're not worrying as much about the organization of the code but rather the functionality of the end user. This could be replacing certain elements in the DOM on a request or containing interactions within the Turbo Frame. I think the two are rather separate and greatly depends on what you're trying to accomplish. You do not need to use Turbo Frame Tags inside of a ViewComponent if you're rending simple things, but any time you need the interactions or updates to be contained to the component (or targeting the component) then the Turbo Frame Tags can really shine.