Their downside is that they have a short life, just a couple of hours. But boy, for those couple of hours, these bulbs are stellar performers. These lamps were very popular for photo studio lighting before the rise of the low cost xenon studio flash units. Theres a problem here though. These days its really hard to get flood fixtures that take big size GLS style ES lamps.
Modern floods use linear halogen tubes.
Times have moved on. So, we need to build something for the job, and here is a cheap and cheerful old fashioned flood. And a couple of words of warning - when I was a lad, my photo books told me these lamps have a habit of exploding. I've never seen it happen, but apparently it can and does, so make sure that an exploding bulb wont compromise show safety. Also, these lamps get hot - very hot.