One of the things rarely mentioned is how condensation forms much more readily on uncoated glass than coated. A darkroom is typically a damp place, and enlarger bulbs heat the surface very quickly. Uncoated glass attracts atmopheric smudges much more easily too, just like uncoated camera filters; you have to clean them way more often. Secondary reflections from uncoated glass can sometimes be seen using a grain magnifier. Even the top glass can have an unwanted
effect in this respect. I never understood why people will spend top dollar for yet another taking
lens they rarely use, but then throw it all away attempting shortcuts in the darkroom.