Dice it becomes boring really fast,at least that is the case for me. Also another major lack of dice games is the jackpot most of the time,very few providers offers you a jackpot if you a hit a specific number like let's say 9999 and win a big share amount of money. For the fun surely the slots are way more entertaining as they offer different gameplay, they offer bonus games or free spins and on top of that, you can also play for a huge jackpot in progressive jackpots slot machines.
Dice is becoming a popular game in most casinos this season and at that level many new players will choose to go for dice rather than slot as it requires some level of skills to play the dice games compared to slot which is pourly base on luck.