Rulers of Nations: Geo-Political Simulator 2
Popularity is not the only reason you can be kicked out of office. You can also annoy specific individuals - such as your military chief - and you can do things that run counter to the policies of your party. That also will result in you being removed.
Policies that are too extreme also result in demonstrations, which can escalate to violence and result in a coup.
None of these have anything whatsoever to do with popularity.
So make sure to make some popular laws and chances if you want to stay in power.
Sure. You can be well-liked by the masses and disliked by the few that actually have power.
It's even easily provable that the popularity feature is working; when it's applied and you're at 100%, you are FAR better liked by various celebrities etc. Turn it off and they like you much less when your popularity falls back down.
Therefore, it is not a superficial change.