Dice are indeed drugs but not the kind of drugs that you're thinking.
There is one type of drug though that would make even the nicest person betray their most precious friend... and it has caused a lot of deaths and wars too... It's called money.
If you think of dice as money, everything will make sense.
Money can buy everything, and people will do anything for money.
That might be the allegory you're looking for.
Not necessarily.
Keep in mind that the DICE is something that is out of social control since it isn´t recognized as something "real", therefore it isn´t legal either.
Now remember that X have only given DICE to minors, and emotionally vulnerable teenagers.
And finally, all this is happening in a closed environment, be it the school or the X game board.
All this combined with the fact that the characters can´t ask for help from people who aren´t involved with the DICE besides that DICE makes the characters feel "special" to have at their disposal something that only they can use but at the same time are in a vulnerable situation and cornered at the same time.
If I had to say my opinion, there is some allegory with the control of the greed of money and capitalism (And surely with other things), but here with the DICE the characters have no control, they are being manipulated by X, and they can´t run away of that, they are prisoners.
While with money, you always have the control and decision to do what you want with that money (Including responsibility), whether for good (Not all rich people are evil people who stab you in the back XD) or for evil ( I don't deny you that there are evil people with money that power makes them worse people).
So my final answer is: It depends.
In my opinion, this is an allegory to drugs and doping.
They have become so hooked to the DICE that it is like they are taking drugs (To be more "intelligent", more "strong", more "handsome", more "charismatic"), they no longer see themselves living without DICE/drugs, they no longerare able to love themselves or accept themselves without DICE/drugs or without being perfect or seeing someone loving the "imperfect"/true version of themselves.
For them there is only the drug/DICE as the only way in their life, throwing away all that their "old and imperfect" identities considered important in their old life, as friends, hobbies, family, studies, future ambitions, and stable and trustworthy relationships...
Just to put the DICE/drug as number 1 in their priorities, and do everything in their power to get the DICE/drug, such as cheating, stealing, betraying, hurting, murdering, and more.
Stopping them to care if they are hurting other people, or if their morality is much worse than it was before taking DICE/drugs, or if they are burying their own future and life with their own hands.
PD: I know there was bullying at the beginning, but I doubt that at that time they could do what each character is doing to get more DICE, the DICE has made him the worst possible people, and I doubt they can return to their normal life or redeem themselves if not They are able to overcome their addiction to DICE.
DICE are drugs.