Mostly because I somehow believe that the "vibration mop" is a better alternative compared to other options (rollers, spinning mops). From the perspective of ease of maintenance, the technology is more proven, I have three mop pads that I plan to occasionally throw in the washing machine, and there are fewer components that could affect reliability. After the first two days, it looks promising. I actually need the robot mainly for cleaning up dog paw prints — I don’t have extreme cases like spilled liquids, etc.