Vegetable oils that are liquid at room temperature are the most convenient to work with. They can easily be poured from the container directly into your fry kettle. They can also be filtered at cold temperatures.
The proper usage of solid fats requires more time and training. For example, solid fats need to be slowly melted over a low heat when first introduced into the fry kettle. There are multiple methods to pack the fryer properly, see here. Also, solid fats must be filtered warm because the fat solidifies as it cools.

Liquid oils are the most convenient products to work with. They can be poured directly from containers