It's not a simplification. It is abstraction. Binding doesn't imply a particular implementation.

A variable binding can disappear entirely. If you bind var x = 42 and never use it, the variable need not exist. If it doesn't exist, then there is no pointer.

If you do use it, constant propagation/folding can again make the variable disappear. If the variable is never assigned, all uses of it can be replaced with 2.

Variables that care captured by lexical closures can be treated differently from ones that are not. Variables captured by closures but not shared among different closures, or not mutated, can be treated differently from mutated variables shared among closures.

The abstraction of binding is more complicated than "every variable is a memory pointer" because it allows more possibilities, which can coexist.

My point is that it's not a simplification, it's precisely how the language works: bindings between values and names (JavaScript has no separate notion of memory pointer; everything is a "pointer"). (Similarly for Python: https://nedbatchelder.com/text/names1.html) Describing variables in this way gives readers the correct understanding, and the analogy of tentacles is no harder than that of boxes. Such things are what I most appreciated, that the author manages to be approachable without sacrificing accuracy.