I think the most concern on vacuum cleaner is bulkiness and difficult to move around. Nowadays vacuum cleaner focus more on mobility than suction power, hence comes cordless, light weight etc

If you are vacuuming mostly in a spot like the mattress or carpet, then yes water vacuum cleaner is better.

If you are using it for normal floor weekly cleaning, try imagine yourself moving the water vacuum cleaning around the house.

It is indeed looks less bulky, but the weight is 7.5kg + 2L water = 9.5kg, which is much heavier than Dyson V10 of 2.6kg weight.

Vacuum cleaner with cordless and good mobility does change my previous bad perception on vacuum cleaner (bulky, tedious, hard to use). But if you think powerful suction and cleaning capability is important for you, then just go ahead with your purchase.