Well emotions are something that we as humans should not repress, it is something that we must bring to the surface,
If suppressing emotions will actually make it worse for the gambler, it is better to let it out as you said, but we as gamblers must still be able to accept the risks for the future, whether we lose a lot or win, we will never be a gambler.
Yes, sometimes gamblers express their emotions by being more daring to bet with a lot of money, but there are also those gamblers who consistently maintain their emotions because they know that the results of gambling cannot be easily guessed and the profits are very difficult to obtain.
Without learning more about self control, they will just getting trap by their emotional and can't do many things except following their emotion to recovers their lose.
That is why self-control is very useful for all gamblers to prevent the emergence of various bad risks in gambling itself. Both in holding back emotions, self-control is also useful to prevent a gambler from becoming greedy and addicted to gambling because with good self-control, gamblers will play wisely, disciplined and careful and they only consider gambling as a fun activity, not a place to make money.