Designed specifically for photography, a photoflood bulb is capable of producing an intense white light for accurate color and shadow control when used in conjunction with other photoflood bulbs.
The lamps were expensive and short-lived, but they were considered a product to be consumed on each shoot, so the price was factored into the job quotes. There just wasn’t any effective replacement until quality LED lighting came along. CFL lights were used for a while, but most of those don’t have a continuous lighting spectrum, leading to color balance problems. The photo lamps, despite their short life and expense, were still the go to solution for a quite a long time.