Adding more games is a good way to attract more players because dice is the most boring game. Where there are some other games then it is usefull for players to kill the boredom. They can switch to other games when they feel boring for dice. Nowadays it is very common for a dice site to add more games, e.g bitsler, bitdice, crypto-games.
Without a doubt, more games = more players = more wager.
But i believe that on bitsler, people are more concern about their dice rather than other games, because mostly people will play and earn everything from their dice not from other games like multicolor or anything like that. And actually it depends on the site itself but most of the sites will want to get more players on their sites so by adding more games it will be more players. And they really need to make the attractive one to make people want to try their new games.
Yes we are mostly focused on dice, but soon we may reconsider

If you guys are focused on dice game then you should make good promotion to make sure people come here and keep on wagering on your dice. Moreover dice game need some fast rolls, if you just can maintain it well, or may be increasing the betting speed, may be people will consider not to get out from here. So you do not even need to make new game just to attract them
Focusing on dice is a good idea, however, I suppose a multi-purpose casino will attract more players. In fact, if they only focus on the dice, they will miss the players in other games. But if they are a multi-purpose casino, many players will come. In addition, optimizing a dice is a good deal, it should be done even if they are a versatile casino, they do not need the focus.