I would advise you not to learn data structures through javascript, it can be quite complicated as too much is abstracted away. Computer science subjects are often difficult to understand in languages like JS.
But the reason to use classes is simplicity, you can just instantiate each new node, instead of doing hacky things like copying the whole object.
instead of
let root = { value: null, left: {}, right: {} }
you can do
let root = new Node();
Also, you can attach the control methods into the class, so they become intrinsic to the node itself. instead of dependent upon outside functions. You don’t have to use classes, life will just be easier by using them.