Why do websites use in-game currency instead of real?

Question

Payment systems

I noticed that on many sites they use game currency instead of real money, for example, on freelance sites, services are paid for with candy wrappers, which can be bought for rubles.
Why is this being done?

Answer 1

If there are N rubles on my account in the game, then the company will owe me N real rubles in case I wish to withdraw my funds.
If there are N candy wrappers on my account in the game, then the company will easily draw N candy wrappers for me right on the screen, if I wish to withdraw my funds.
Wrappers are nothing but what is drawn on the screen.
Rubles are real money, and their value in my account represents the amount of debt to me.