I thought someone might bring this up :-) Good question.
I'm the author of the first question you reference. I'm also the person who commented on the second question, saying it's likely against the "opinion-based" rules.
I agree that this is a discrepancy. I also concede that this is hypocritical on my part, especially as the first question has a lot of upvotes.
When I asked the first question you reference, the site was quite new - perhaps a couple of weeks old. I was as guilty as any new member who hadn't read the Help Center guidelines, and I was genuinely interested in getting an answer to my question. At the time I wasn't a member of the Ethereum Reddit boards, which is where I now suggest people go to ask opinion-based questions. At the time I also hadn't yet had the experience of flagging other questions for closure - it's possible that I didn't know that "opinion-based" even had its own closure category.
The fact that it wasn't flagged by the rest of the community, or the moderators, also suggests that at the time best practices hadn't yet coalesced. Over time the site has changed, and the community has become more experienced at categorising what is a good or bad question with reference to the guidelines.
There are other categories of question that also exhibit this discrepancy.
There are some very useful questions that would now almost certainly get flagged as "3rd-party application", others that would now be "too broad", and so on.
Having said this, both the questions you reference have clearly been useful to the community. CPereez19's question has an above average number of votes and has been favourited a good number of times. The community clearly believes it to be useful.
But as I mentioned in the answer to CPereez19's Meta site question, there's perhaps a slippery slope if we now start to allow opinion-based questions more generally. Good questions exist in all the categories which we consider off-topic, but in my opinion it would be harder to moderate such questions and keep the quality at the level we have now.
I'd be interested to hear the opinions of others :-)