If you want to use only basic functions of UiPath and activities from official marketplace - actually you don’t need good knowledge of C# or even
vb.net.
But if you want to make powerful robots you could need to use some ready libraries and code snippets that exists in C#. So you will have ability to create your own activities and use them in your robots.
So yes, professional companies that make robots for big enterprise - want to have experienced people who know how to do that.