It's always nice to mix things up a bit and explore some other communities and topics, of which there are many.
At the same time though, you don't want to force yourself to write/ post about things you're not interested in. I've tried that, and it takes the fun out of writing in a way.
I've experienced that too. Writing on topics that I'm not interested in is always hard, sometimes totally boring! Better to always write on topics that interest us and have fun along the process.