Question

I’m wondering why should I use a class that inherits from the EventArgs class instead of using a custom class that will do the same job for me when passing event data?

Answer 1

You don’t have to inherit from EventArgs, but it allows people using your classes to use and handle generic *Handler(object sender, EventArgs e) declarations.
If you don’t inherit from EventArgs, then they have to use explicitly typed

*Handler(object sender, YairsFakeEventArgs e)

The same goes for just using custom delegates but they are a lot more explicitly different.