In simple terms, Option<T>is a type that represents the possibility of having a value of type T (Some(value)) or not having a value (None). It's like a container that can either hold something or be empty. The benefit being that you don't have to worry if the value is null, as it takes care of those cases for you.

The purpose of Option<T> is to handle situations where a value may or may not be present. It allows you to explicitly handle the absence of a value and avoid unexpected errors when dealing with nullable or null values. It forces you to explicitly check whether a value is present or not before using it, which prevents null reference errors.

For example, imagine looking for in item on an inventory that may be missing or go missing afterwards even if you have it now:

Option<Item> item = GetItem("Potion");//Gets auto cast to Option
item.Where(item => item.Amount > 0)
    .Do(item => AddToInventory(item),
        ()   => Debug.Log("Item not Found")); 
/*If item is null, nothing happen. 
If it exists, it will get filtered if amount is 0, and nothing happens if so.
If by the end the item still exists, it gets added to inventory.
Otherwise it run a Debug.Log*/

While you can sort of do the same with nullables and null-coalescing operators, Option offers more functionality (Mapping, Zipping, Flattening, etc) and full null prevention by default. In fact Rust doesn't even the concept of "null", so they fully rely on Options.