Primedice is reputable and one of the earliest dice site that operates until today. Until now, they are well known and has a good traffic of dicers. The reputation that it got to the community can't be compared to the new dice sites that are coming to compete with it. I've seen some dice sites that became hype few years ago but wasn't able to beat primedice.
True, they are popular and I don't think a gambler would not know them, also they are related to stake.com that are also popular now.
No special purpose imho, he/she just want to share something that he/she found in coinpedia. Take a look at his/her post history, there are some similar posts which comes from coinpedia. Not really sure why he/she did it but I he/she just posted it then leave it without replying to the thread he/she just made.
Indeed, that's why I don't like to see people posting this kind of information where it looks like a bot who is doing it.
An OP should also be active in the conversation as eventually people will ask, give idea on the subject that they think is interesting.