In theory it shouldn't matter, in reality it probably does matter to some extent, whether that's actually distinguishable is probably the right question. Ultimately though, you get to choose your own username here, so if you didn't want to get stereotyped or profiled because of your username, you could pick something that you deem less likely for that to happen. Ultimately for me, that wouldn't influence my decision. If people don't like my username or Welsh people, then that's fair enough
. It's not going to be a factor in picking a username.
Although, generally it's not something that pops into my head. I imagine many users here don't even look at the username of the poster unless they particularly like or dislike what was said.
Your ranking up is not determined by your name on bitcointalk. If you contribute good in discussions, you would be an established member on this forum. But it is good to give yourself a name not attributed to something bad.
Also know that username can be different from people's real name. Do not make this confusing.
While this is probably true for the most part, there will be some subconscious bias to usernames, that's just human nature, which I think is what OP might be onto here. For example, and this is a rather loose example; If you like cars, and someone else has the name CARLOVER3948389, then you might be more inclined to give that user merit or pay more attention since they share a common interest. It might not be a massive amount of bias, but I'm sure there will be some there if you did a case study on it. I imagine there's been other studies in a similar vain that have been conducted.