Whether separations make a difference for anything but price depends on the separation.
I have a 58/5.6 Rodenstock Grandagon with baad separations. Spectacular rings of fire, silvery spots, ... Looks like hell, shoots well.
Years ago I bought a 16/2.5 Zeiss Luminar. There was balsam puddled around the periphery of the front glass, examination with a magnifier found voids (bubbles) between the cemented pair. The lens had much lower resolution and contrast than a good 16/2.5 Luminar borrowed from a friend. Much worse.