Obviously all decisions will come back to the casinos themselves, they must also learn what advantage they get by adding one currency, like giving them more users or something. Or they don't get any profit they want if they really add new currency as a means of payment or betting.
Of course here is mostly just a suggestion and input for the casino to consider, and the decision is clearly in their hands completely. Whatever they decide is the casino team's deal.
I’m not good on the license but adding some fiat currency will give some extra work for them since they need to setup payment option for fiat deposit. Also are you depositing using your fiat because most of the user here especially in crypto casino industry use crypto on deposit while most of the game automatically converts all bets in $ or €.
I will try to suggest your concern on live support since no one from you guys that requesting here made an official request on the casino itself. It just take few seconds or minutes to use the live support and make that request since the more user that will request means the high chance that this will be granted immediately due to the interest.
Afaik the main discussion is not about adding new payment system, but it is just like a system to show user's balance in different currencies and make users able to bet using the currency as they wish.
Means that the casino do not need to setup payment option for fiat deposit, what the casino need to do is just to add more currencies in the option below:

Currently in livecasino, there are 4 currencies to choose in Livecasino as above screenshot and the main discussion above is to add IDR in this option, not to add payment method with fiat.