That's a 'key feature' for a rather narrow niche of players. Which makes a lot of sense - voice chat itself was once a special thing for srscat gaming enthusiasts. The trouble is, the voice chat products themselves got stuck there, even as networking, median hardware and multiplayer gaming itself got a lot more popular. Discord is just a better product, not for 'the mass market' but generally and it's worth studying rather than dismissing its success especially if you want better voice chat tools that also meet your specialized needs.