I often play dice, it's simple and entertaining. I have been using this website for many years: primedice.com, it is probably the most popular in dice sites.
Dice is indeed popular and back in the starting days of primedice and its predecessors back in 2013 it was the most popular game. As time passed more development in tech happened and more games were developed to replicate the real casino games. Slots is what gamblers drool over, if you ever visit the Vegas strip you will understand. It is similar here too, these are easy to play games and are often the maximum spending site for gamblers.
But for a subjective statistic, one must run a survey.
It was famous casino game way back before and lots of people pointing out that this is the people's favorite. Lots of people also having a good discussions about strategies they are using, but now it seems the fame of dice game is fading out since people's attention has been shift to other games. Right now we can see that lots of people talking about slots so maybe from that game they see a potential to earn huge especially if they hit the jackpot on that game.
But it would really more better if OP or someone will run a survey or poll about those game so that we would know the updates about what currently people like to play. For sure everything will be seen once people cast their votes on the survey and choose their favorite games.