Discord is blocked in China, and a large number of people in China are not willing to use VPNs.

Discord uses themes that do not meet minimum contrast guidelines (#747F8D on #FFFFFF is 4.06:1, failing WCAG AA for normal text).

Discord says third-party clients[1] and even client-side CSS modifications violate their ToS https://twitter.com/discordapp/status/983359562458849280

[1] https://old.reddit.com/r/discordapp/comments/8tukek/ripcord_...