Yes. Without it, you'll need to empty the tiny dustbin every 1-2 runs. Self-emptying docks hold 30-60 days of dust. It's worth the extra cost.
The Roborock Q7 Max+ at $449 is the sweet spot — LiDAR navigation, self-emptying, and good suction without the premium price.
Best overall — vacuums, mops, and empties itself
Best for pet owners — tackles pet hair like a champ
Best mopping — square design reaches corners
Best mop lifting — extends mop arm for edges
Best mid-range — 80% of flagship at half price
Best budget — surprisingly good for $129