Draining oil from the sump plug pulls out all the muck etc that can collect in the oil pan,giving as good a job as you can get without dropping the pan, which we can't do on our bikes, these pumps leave the worst dregs behind.
Our bikes need good fresh oil,as long as your careful doing up the sump plug, maybe installing a new copper washer with fresh annealing so it has not gone hard, and draining as per Suzuki instructions, is even easier than faffing about with pumps for a less thorough evacuation of the old oil.
Just my thoughts.