You highlight an important point: in a big project, where a lot is going on, your thing might be going on without you realizing too. If you start the work witho

You highlight an important point: in a big project, where a lot is going on, your thing might be going on without you realizing too. If you start the work without checking past attempts and current claims, you risk wasting your effort. In smaller projects, the chance of making an obsolete contribution is lower due to things moving slower in general. On the flip side, there are people who announce their intention and never follow up on the promise, while potential new contributors may think the problem is getting solved. As the maintainer, I'd rather have them announce nothing. Then there are ideas that are not easily expressible in worrds. Sometimes you just have to show it for others to be able to meaningfully consider the topic.