Absolutely! For any tool, software, or service that is an integral part of the 3D printing landscape, questions about how to use them should be on topic here. When folks go searching for answers about the products and services they use every day, I sure would like them find the answers on this site. As a matter of fact, these project teams often have communities of their own, so we should encourage them to become part of the ecosystem of this site.
It's a big growth area of growth for this type of Q&A.
Now there may be a line where service-related questions are simply too far outside the subject of 3D printing to be appropriate here. Stack Exchange works really well for technical support, as long as we're not trying outsource their entire customer service channel here. I wouldn't expect to host (for example) a question about a rate hike on another service, or a bug report or feature request. But we haven't hit that line. It is usually better to wait for actual examples of problems before trying to too many rules around this kind of thing.
So I wouldn't fret this. Until conditions dictate otherwise, the subject(s) you cited seem well-suited to this Q&A.