Why symbol-value throws a void-variable error with a let form if lexical binding is on? [duplicate]

Question

Here's a simple example from the manual:

;; Here the symbol ‘abracadabra’
;;   is the symbol whose value is examined.
(let ((abracadabra 'foo))
  (symbol-value 'abracadabra))
⇒ foo

Why does this throw an error with lexical binding? The variable is bound in the let, isn't it?

Emacs 26.2