There are many good reasons of choosing the programming language over a markup language. C# has countless of features, both functional and syntactic: conditions, loops, methods, formatting, iteration, recursion, etc. Additionally, each of those features is well supported by all major IDEs. Writing your presentation layer in a proper programming language does not only rely on your existing skills but also gives you access to tools such us code completion and IntelliSense. Moreover, using FluentAPI helps with keeping the code concise and easy to change.

At the end of the day, it all depends on how you use the technology, doesn't it?