Why SICP?

What's so good about SICP? Isn't LISP completely useless?

when i first learned perl i found it entertaining to see how much of the program i could write without using variables. that is, the output of one function going directly into another, forming an unbroken chain like this: function1(function2(function3(function4(input)))).
i didn't realise it at the time, but i was mimicking functional languages.

then i realise "hey, avoiding the use of variables is actually really inefficient and obfuscates my code", at which point i gained satori.
functional programming is for immature chumps like FV.