They are different things, so it is not a matter of being advantageous to use one or the other. They should be used for different purposes. Although they could be used together.
So much so that ASP.NET WebAPI has become an integral part of ASP. NET Core . You no longer use one or the other because essentially they have different operations when you want to do one thing or another, but the basis is the same.
MVC assumes that the user will access sites which are collections of pages to view. WebAPI only returns results, it obviously does not have visions, the V of MVC.
WebAPI has always needed a simpler structure, but if you think about it they need models (the M) and need, if not the controllers (C), something very similar. That's why it makes more sense to use a single framework .
Working with WebAPI is easier for a simple reason, it does a lot less. And this is why if you want to present pages, WebAPI is not an option. At least not alone.
Of course you can use WebAPI to get the results and assemble the pages with different technology. But I doubt that makes any sense to you. You can make third-party consumers your API. For others, understand other programmers or other applications you make.
As the name says WebAPI is to create access APIs in the web format. API is for programmers to consume and how best suits them. It is not for building entire sites.
You can even make the form completely on the client side (type SPA ). I would not need MVC, but this does not work well for sites , works best for applications.
So WebAPI does not assemble a form for you because it's not your goal.
I think in this case you should use MVC.
Or if you're going to do something simpler, consider ASP.NET WebPages . It's curious how hardly anyone knows this. I see many programmers killing themselves to use ASP.NET MVC to make sites very simple simply because they do not know everything that exists in ASP.Net. This technology enables sites in a way that is analogous to pure PHP, using only what is already available by default in the language. WebPages gives an entire infrastructure that helps a lot without imposing a development model.