I stumbled across this question. Just in case something happens to that question or its comments, here is a Wayback Machine link. I wasn't quite sure about if Bitcoin was on-topic, so I didn't flag it or vote on it. I still haven't. Here are two comments that were attached:
This question might be better answered on the Bitcoin SE site 🤔
This question is not releated to Ubuntu , you can ask this on Bitcoin SE , Only questions about Ubuntu and it's official flavours are accepted here. We are sorry that you cannot ask questions about bitcoin here.
But... Ask Ubuntu has a bitcoin tag, with the top-question in that tag scored at 53 at the time of me writing this, it looks like Bitcoin might be on topic.
Personally, I don't have an opinion one way or the other, but I do think it is worth clarifying.
So, is Bitcoin on-topic on Ask Ubuntu?
Edit to address the comments:
The main problem I have with that question is OP mentions some tutorial, but doesn't link to it and doesn't specify what exactly they did to arrive at their current situation. I'll VTC as unclear
Of course, I think it is totally fine to VTC as unclear if the question is unclear, but... the comments on the linked question didn't say "Your question is a bit unclear, please  your question to include the link to the tutorial. Also, you could ask on Bitcoin SE". Instead, it said the question was off-topic because it was about Bitcoin. That is why I wanted clarification. Flagging because the question is unclear is fine, but I wasn't sure about if it was on-topic or not.
I like that you kept the emoji in my comment. It's like a signature 😬 – My suggestion that the question might be better answered on the Bitcoin SE site wasn't so much a "this isn't Ubuntu" question, but more of a "it might be better to ask experts about RPC credentials and authentication cookies" ...
(1) Emojis are fun. (2) As to your comment itself, I'm fine with adding a link to Bitcoin SE, and I think your comment was good. Honestly, I included your comment simply for context, not because I disagreed with it or because it was confusing.