Organization scheme, ease of use of the voice channels, cross platform compatibility.
We briefly looked into discord alternatives. Element x isn't mature enough, schildi chat could be viable. Revolt seemed to be the front runner, but the voice chat was awkward to use since it didn't show when people were in channels, and the noise cancelling of discord was sorely missed.
The discrepancy you're pointing out across different countries is at most 18x, according to your article.
Let's ignore, for a second, that "richness" needs to be considered in the context of COL. Yes, 1% of someone salary could make an impact in Tajikistan. But the cost of a meal for that potential donor could also bankrupt someone in Tajikistan. But let's ignore that for now.
18x an average persons salary is a fart in the wind when it comes to the rich. Take a look.