my experience doing land nav with night vision is... definitively better to have a monocular mounted on helmet than something mounted on a rifle. Imagine seeing absolutely nothing except through a toilet paper tube roll. Now imagine it's mounted on your rifle instead of hanging in front of your eye.Ukraine experience? Perhaps it is much better to have NODs on rifles/weapons, vehicles or fixed mounts, rather than reduce situational awareness which occurs with monocular helmet mounted NODs, at least for line infantry.
My guess is the digital tech is just not mature enough. The image quality looked pretty mediocre, and they do suffer from lag which is quite nauseating from what I heard of people that tried the system.