I dont get it, why are choice items so popular? I mean, it's not a good thing you gotta use only 1 move until switching out, isnt it? :|
In chandelure, Never use it except scarf which
In general : It increase speed or attacking stats by ONE stage meaning if you have XXXmon with 400 attack you give it choice item it become 600.
The power boost is huge as if you barely KO tyranitar for example dealing 70 %, now you do 105 %. ANd also prediction exist. Its not like you play pokemon with only 1 POkemon to solo team
And scarf can make slow pokemon more useful allowing abuse of high attack stats or make fast pokemon able to beat boosted pokemon's speed