Premium open source plugin

I plan to release a premium plugin when I hit the requirements and I want to know what you think of having the source code available.

The cons with having it open source is that people will build it for themselves and never pay, but I believe having it open source so people can submit bugs, feature requests or even contributions weigh up the pros.

Is it allowed to accept contributions for a premium plugin without giving back? Is it stupid to open source it? What’s you thoughts?