Python Nodes

So in the Linear Data Structures Python course, in the Nodes lesson, instead of just directly setting Node.link_node and Node.value like this:

Node.link_node = AnotherNode
Node.value = Value

Why are we using getter and setter functions like these to set our values?

def get_next_node(self):
     return self.link_node

def get_value(self):
     return self.value

def set_next_node(self, node):
     self.link_node = node

Is there any advantages to this design or should I use either direct assignment or getter/setter methods?