Honestly I haven't been around the steemit blockchain for all that long (Dec. 2017) but I still find myself learning new things about it every day. The Dust rule does make sense as some of my earlier beginning articles would earn very small rewards and then I'd see them disappear at the time of payout. I always just figured this was because the price of STEEM/SBD must have gone down at the time, which rendered my post payout to be worthless. Its funny how one tends to draw connections between events even if this correlation does not really exist! Lol Thanks for shedding some light onto the real reason why some of the rewards seem to drop off at the last minute.