How reliable age certification at Google Play is? So far I've been trusting in PEGI certifications nearly as in bible.

Today, I found Alchademy game, which has PEGI 3 age certification, but deeply in the game's desc you can find something like this:


  This game is not intended for children and may have some content that is inappropriate for children under the age of 13.


Please, explain, what am I missing? How can a game pass PEGI 3 certification with such a note?

Based on above, I come with the conclusion that PEGI certifications at Google Play are completely worthless and when deciding whether particular app is or isn't applicable for my children, I must always dig description or -- the best -- install and play the game myself.

If that's truth then what is the reason in fouling people with that whole PEGI stuff at all?
Disclaimer: I don't develop Android apps so my answer might be lacking. I hope our residents developers will provide more clarifications if necessary.
According to Content ratings for apps &amp; games, The rating of an app is done by independent 3rd-parties not Google. The app's developer fill a rating questionnaire, then independent 3rd parties rate it:

To receive a rating for each of your apps and games, you fill out a rating questionnaire on the Play Console about the nature of your apps’ content and receive a content rating from multiple rating authorities.  Since they are independent third party rating authorities, each rating authority uses their own methodology to assign your ratings (see Rating authorities &amp; descriptions below). The ratings assigned to your app displayed on Google Play are determined by your questionnaire responses.

It is possible based on the last sentence that the responses to the rating questionnaire prompted the rating agencies to rate the app PEGI 3 while the developer(s) state(s) even on their own website that:

This game is not intended for children and may have some content that is inappropriate for children under the age of 13

Thus, the app should be rated PEGI 12. As a comparison, the game is rated +9 on the Appstore.
The rating can be inconsistent as shown here where keyboard apps with the same content are not rated the same:

The Fleksy app, which has been on the Play Store for around eight years at this point — and per Play Store install stats has had more than 5M downloads to date — was PEGI 3 rating until earlier this month. But then Google stepped in and forced the team to up the rating to 12.



That’s not the end of the saga, though. Google’s Play Store team is still not happy with the regional age rating for Fleksy — and wants to push the rating even higher — claiming, in a subsequent email, that “your app contains mature content (e.g. emoji) and should have higher rating”.
Now, to be crystal clear, Google’s own Gboard app also contains the middle finger emoji. We are 100% sure of this because we double-checked…

In the case, of the link article above, it was Google that forced the rating change not independent 3rd parties. After the developers complained to International Age Rating Coalition, the rating was then restored. It shows that Google can manipulate the rating.