why do casinos limit bonus amounts based on how much you deposit

So I keep running into these promos where the bonus matches your deposit but only up to a certain limit. Like, you could drop a big amount, but they’ll just cap the bonus and not match the whole thing. Kinda seems odd, right? It’s not like the casino doesn’t want your money.

I figure it probably has something to do with managing how much risk they take on, or maybe it keeps folks from just whale-ing the system. Still, I’ve seen some sites even get stricter if you use crypto instead of fiat. Does anyone notice patterns in how these caps work, especially for roulette or crypto players? Just trying to make sense of how these limits get set.