In my opinion the most pointless well known cartridges are the 224 Valkyrie and 6.8 SPC. The Valkyrie was intended to use heavier projectiles than the 223 Remington for better BC values however both can use the 90gr high BC projectiles and the Valkyrie only has about 100 extra fps compared to the 223 when using those and they're identical with lighter bullets. I don't see why someone would hunt down the Valkyrie when 223 can already do everything it can and they've probably already got a gun chambered for it. The 6.8 SPC had some merit at it's time of introduction, however since then, the 300 AAC Blackout cartridge has arrived and 7.62×39 ar-15s now exist, so I don't see why anyone would chase the proprietary magazines, rare uppers, expensive ammo, and rare projectiles associated with 6.8 SPC, especially considering 7.62×39 performance comes close to it, and with 6.5 Creedmoor around, the case becomes even worse for the 6.8 SPC. What is the most pointless cartridge?