It’s used to protect against water ingress and provides rust protection, as well as reducing friction experienced by machines.
It has a high viscosity, so it’s a better choice for applications where liquid lubricants such as oil wouldn’t stay in place. This means grease and oil are not interchangeable.
Thanks to it's water resistance, it can act as a sealant and is commonly used in the automotive industry for tasks such as chassis, wheel bearings and gears.