Because for many players, it's not worth spending money on the game, because it's just a way for them to pass the time, there's no need to spend money on it, as long as you have good skills and enough patience, you can still play the game Play for free to get Path of Exile Currency items.
But there are still many players who have a strong desire to win and are more serious about everything, including games. Therefore, when Path of Exile aroused his great interest, he was willing to invest time and energy. But no matter how good the game is, there will be boring farming missions.
To save more time to do more meaningful things, many players will be willing to buy POE orbs. Buying POE Currency on RPGStash is equivalent to a bottle of water, but it can save half a day or even a day of work, which is the very costly benefit.