Nearly everything I have ever made has run on Linux. It depends on the purpose of your application.

Some bonuses about Linux, out of the box with RedHat you get python and C++ while you need to jump through a few hoops on Windows.

In many cases, the things I make are on networks that do not have internet access and I am not allowed to install anything. Having everything supported out of the box in Linux makes deployment much easier.

Grids and computing clusters are usually Linux based. Git and svn are also out of the box for Linux. Windows makes you dance for them.

Could go on, but it really depends on your application. C# in Linux doesn’t make much sense since you would likely push for python, JavaScript or something else.

Linux is still worth knowing though, like it or not it is a really popular OS.