Sage Advice is nothing but tweets
As far as I'm aware, Sage Advice (i.e.
sageadvice.eu) is just a person who collects tweets from various people who helped with DnD 5e and its rules (primarily Mike Mearls and Jeremy Crawford) and is not associated with WotC in any way. In fact, the name is even annoyingly confusable with the actually official rules interpretation publication: Sage Advice Compendium.
In general, I've seen people consider tweets to be worse than useless
I've generally noticed that people have gone from using Crawford's tweets to justify claims to avoiding even referencing them (perhaps because people will downvote posts solely for using them).
I've seen a lot of people say that the tweets only showcase Crawford's (or somebody else's) viewpoint at that specific point in time. In fact, Crawford has made tweets directly contradicting (or correcting) previous ones, which has not helped to increase their validity or helpfulness when it comes to answers here.
I've similarly seen people say that Crawford, despite being the lead rules designer, is just a single person whose opinion on interpreting the rules means as little / as much as anybody else's and so the tweets should not be used for evidence in answers.
I've also seen newer users use Sage Advice and then seen others leave comments explaining that these are not official rules and should effectively be discarded from the answer. Given that some people do find the intent of the designer of the very rules we are trying to interpret to be important, I've also seen these comments not go particularly well.
How have I changed?
Personally, I have stopped using tweets in my recent answers (there are a few exceptions) as I got tired of the comments people inevitably left. I have also been leaving comments under answers where Crawford has a tweet that might be considered helpful. These comments are often: "For whatever it's worth, Jeremy Crawford agrees in a tweet" (with a link to the tweet (not SA) and quoting the tweet itself) whereas before they would not have included a "For whatever it's worth" clause.