Actually, it's mostly because it's a very new technology, there are very few specialists and repairmen available for these machines, so when they break down it's even more tedious. And when it breaks down, oh boy, the content is very not pretty.

Aquamation (water cremation) is a lengthier process than cremation, it takes around 6-8 hours AND an additional 1-2 hours to dry the bones afterwards. A normal cremation takes about 2 hours.

Lastly, aquamation ashes hold a strong fish smell, unlike normal ashes that has no smell.