It plays a part in what is decided, yes. But only a part, and there will be other reasons that play into what gets selected and what doesn't. That said your examples are about the worst to pick :) e.g. rewriting code to work on GPU is a massive undertaking, which obviously is a big negative against developing that, no matter how many vote for it. But always vote for what you want regardless of that, and know it does have an effect on what gets picked.
