Interesting read
https://stargazerslounge.com/topic/3...-night-vision/
Seems I was wrong. The eyepiece is to simultanously focal reduce and reach focus in a dob (big light bucket with fast focal ratio = win).
I agree eyepieces are going to stick around for decades. NV price is the big kicker and the point remains the very best NV you can purchase (imports/exports are classified as military equipment) still don’t do colour.