Money is relative to the wealth of the individual. For most, 1M USD is a lifetime of money, if not several lifetimes in some places. However, for the whales and the big players, 1M USD is just change. It is difficult to understand for people who will struggle all their lives to make a living for their families, but there are people out there that will loose that amount and will not even blink.
You're right, mate. Only rich people can afford to spend enormous amounts of money, even for a single use of their money, for example, shopping.
But for those who don't have much money, having 1M USD is still a dream and we will feel frustrated if we spend it only on gambling.
That kind of money can provide for our living needs for many years for people who live in countries where the cost of living is not high.
We can only learn from what others have obtained so that we can take what is good to apply to us and leave what is not good.
It's indeed, obvious that the gambler who did that is rich, many members here regretted that he made that bet, while the bettor himself can't see any regret or remorse for what he did.
For rich people, they won't feel the value of 1M$ but for those who aren't, of course maybe even just 20k$ is too much regret for us or maybe we haven't agreed to bet that amount too.