All of the same things that are wrong with Slack, discussed in the OP. Don't use nonfree platforms to collaborate on free-as-in-freedom software. They also appr

All of the same things that are wrong with Slack, discussed in the OP. Don't use nonfree platforms to collaborate on free-as-in-freedom software. They also appropriate "server" terminology to dilute stuff which actually puts the users in control - unlike typical "servers", a Discord server is anything but - they run on Discord infrastructure and the user has little to no influence over their adminsitration.