Watches

I’m really curious about the point of lume, besides the obvious. What I mean is that through casual wear it may charge but also goes dark again within 3minutes of being in the dark. Any profession that required lume hands almost certainly switched to digital/wrist computers, but what was the original process? If I know I’m going to be saturation diving in the afternoon, do I have to put my watch under some lamp all day. It’s just all a bit silly compared to something like tritium tubes with an actual constant glow.