I used this technique a lot at one time - Why?
Lessens tension in the guitar
Lowers the action
Widens the 'playing area' in the neck that helped my fingers move around
Easier to 'bend' notes
I enjoyed the 'twangy' sound especially playing some 'old time' of 'folk blues' stuff
Could sing in G flat playing G chord structures if I wanted and that suited me with certain songs.
Didn't burn my fingers so much after 3/4 hours of playing or practice

I don't do it now I just stick ultra lights on a Martin D41 (sacrilege I know but so what) If it works for what you want then just do it. There's no 'right or wrong'??