1. Differentiators. ("Gamechangers" in the article.)
2. Tablestakes. ("Showstoppers".)
3. Niceties.
I like "tablestakes" because it describes the presence of the feature and not its absence. Also, a betting metaphor implies that this is a moving target. The tablestakes can be raised on you if all your competition adds some beloved feature. When Dart first launched, non-nullable types would have been a differentiator. Now it's tablestakes.
Languages are interesting because you have a very limited budget for differentiators. Users have a finite appetite for novelty in programming languages, so you have to spend that wisely on a small number of very compelling features.
The third "niceties" category is interesting. Those are features that please existing users but are not compelling enough to attract new ones. There is an argument that you should not focus on those if you are trying to grow your userbase since by definition they aren't compelling enough to attract new users.
But I believe they can be important for growth. Shipping features that bring joy to existing users can help turn those people into your product's evangelists and, especially in programming languages, you really need that.