According to PlasteringWorkshop.com, they make it much easier to mix cement.
Indeed, the website said that by using a mortar bucket, you can make sure the mix is constant and the same colour all over.
However, PlasteringWorkshop.com suggested that builders should try to make sure they do not overmix their cement.
The site said that if it gets too wet, it will simply run off the trowel.
It also advised against going too far in the other direction, as dry cement will simply fall off whichever implement you are using, such as a Rose brick trowel.
Using a product such as a mortar box can be particularly useful on a relatively small building job, where you don't always need a larger mortar mixer.
They are usually made from plastic or steel and are designed to be very easy to clean, making them long-lasting and reusable.