Halogens have high light intensity between 650nm-950nm, which encompasses the red region of the spectrum, making them useful for budding.

It's true they give off loads of heat, but some people don't have problems keeping their temps down. In fact, some people use heaters to keep their temps up, making halogens an attractive option. I wouldn't suggest using halogen as a primary light source, but I'm using a halogen to supplement my MH during budding.

peace,

joe.