"Monero is, in fact, the most scalable cryptocurrency when used privately, and even when compared with default, transparent Bitcoin usage, its transactions are only ~3-4x the size of Bitcoin transactions today. Monero’s transactions were much larger in the past, but the Monero community, researchers, and developers have worked hard to improve the efficiency of Monero, bringing transactions down from ~13kb when RingCT was first introduced to ~1.4kb today."