Many of the older flash bulbs had more power than electronic camera mounted flash units and some argue better quality of light. I’ve not used them much, but am really curious. Here’s an article on the Film Photography Project page that I read recently after a customer asked me about where to find flash bulbs.
The Lowdown on Flash Bulbs Guest blog by Steve Ringrose Editor’s Notes: Millions of vintage cameras (especially the Kodak Instamatic cameras here in the US
Source: Flash Bulbs – The Lowdown! – The Film Photography Project