Underlying "How deposit bonus works?" is one fact: a coin's price keeps moving while it sits in an account. A balance held in coins changes value even when no bet is placed. A win can shrink while it waits for withdrawal, and a losing session can look better or worse than it really was. How a casino displays and converts a crypto balance decides how much of that movement reaches the player, and stablecoins remove most of it.
Bonuses at crypto casinos are fixed either in the coin or in a regular currency, and the difference shows over a long wagering period. A bonus counted in coins moves with the market, so its real value on the day it converts can differ widely from the day it was granted. Wagering targets and maximum bets follow the same unit. The bonus terms name the unit, often in a single line under the headline figure.
Casinos show crypto balances in one of two ways. Some keep the balance in the coin itself, so its value in everyday money rises and falls with the market. Others convert each deposit into a regular currency on arrival and show that figure, which freezes the value until withdrawal converts it back. The account settings or the cashier page state which approach applies, and the difference decides who carries the price risk while funds lie idle.
Every conversion uses a rate, and the casino's rate is rarely the market price. A small spread between the two works as a hidden fee, charged once at deposit and again at withdrawal when a balance is converted in both directions. Comparing the rate on the cashier page with a public price at the same moment shows its size. On frequent small deposits the spread can cost more than the network fees.
The small gap between the casino's rate and the market price is charged at deposit and again at withdrawal, and on frequent small deposits it can exceed network fees.
Some casinos keep it in the coin, so its everyday value moves with the market, while others convert deposits on arrival and freeze that value until withdrawal.
A stablecoin is designed to hold a fixed value against ordinary money, so the balance keeps its everyday worth from one day to the next.
The casino's own rate, which is rarely the market price; comparing it with a public price at the same moment shows the gap.