Let's say you want to clamp a value v to max constant 20. You could do it with code
if (v > 20):
v = 20
But this is shorter and looks better in code:
v = max(v, 20.0)
You can use min max to clamp a value to the range (Godot has a clamp function, but still...)
v = max(0.0, min(20.0, v))
You can nest them, if you want to use more values
v = max(v1, max(v2, max(v3, v4)))
I personally use them a lot in my current Java project.