>>33436939Rainbow is basically a free, 4-turn serene grace for all allies, so it surprises me it doesn't get used more often in some kind of meme team that abuses moves with 30% chance to flinch and stuff like that.
The other 2 pledge effects (sea of fire, swamp) are not that great as the first is negated by rain while the second is pointless with thunder wave or tailwind in doubles, so it doesn't surprise me as much.