Because every Capture is a unique device (in practice), it makes no sense that “Set parameters as default” should apply to ALL captures.
as I understand and use it, the goal of default parameters is to store “my favorite” settings for a specific device. That works well when the device is a specific delay.
But if you mix amps, overdrives, distortions, etc. having a single “default parameter” across all of them just doesn’t work.