You don’t get a side target that enables you to great-tune parallax, which is the perceived alignment of the reticle and target. You don’t get yourself a reticle with valuable keep-over or hold-off references. So you don’t get illumination. I assume they just have to be pretty much as good. https://rifle-scopes56666.blogzet.com/the-basic-principles-of-riflescopes-44507145