# THIS:
onready var foo = $Foo

# IS THE SAME AS:
var foo
func _ready():
    foo = $Foo

# IS THE SAME AS:
onready var foo = get_node("Foo")

# IS THE SAME AS:
var foo
func _ready():
    foo = get_node("Foo")


# You could not do any of that and everytime you want to access "Foo" do:
$Foo.some_func()

# But then if "Foo" is not in the same location, for example you move it into $YSort/Foo,
# now you would have to change every line that uses "Foo" to $YSort/Foo