In fact, there are other considerations besides familiarity, Open source is an important reason. Another benefit is to keep my development environment the same as my server's.
The game development, not only need the client's front-end technology, also need the backend server technology. However, most of the time the server may have no problem, once appear problem, it is necessary to solve quickly. if the development environment is the same as the server, it is very beneficial to achieve this.
Review after game finished, I think choosing Linux is correct.
First, almost all needed game tools can be found in open source software, gimp, blender, imagemagic, kazam is really very good, a lot of other tools are easy to find also. Especially for the first time developing a game, a lot of things need to be explored. It will be wasted if buy a lot of commercial software from the start, but finally may be abandoned.
Second, the game development time is very long, many tools need to learn, many things are the result of a lot of hard work,the development process should be built on a platform which may be used for a long time, I think Linux is a good choice.