I learned to shoot double action by staging the trigger on two Colts. I got pretty accurate after a lot of dry firing and as much shooting as I could afford. This is fine as long as you are shooting Colts and are shooting targets. I've never been in a gun fight, but I bet that finely practiced trigger staging would be forgotten quickly. For the last 20 years I have shot mostly S&W's and have learned to use a straight pull through technique. More practical and plenty accurate as long as you practice. If I slack up on practice I find myself staging the trigger, old habits die hard. Main thing is practice, practice, practice.
