Breathy singing can be extremely effective as part of the way to add a different and contrasting quality right next to slack. In pop it is often used as a means of drawing emotional attention to a particular lyric, or as a means of avoiding vibrato!

Some artists, such as Ariana Grande will us it for Entire lines of music in something called "whisper pop".

The key to getting breathy singing to be effective is to turn up the treble both in the mix and in your voice itself. Keep the larynx high, and the back of the tongue high so that the breath has a little more turbulence/wind sound and it carries a little more of the treble frequencies. This will keep your breathy tone from sounding too "hooty" or dark, and it really plays well with common post-production plug ins.