Yeah, I was also going to say that conflating trivial syntax and "supremely easy to learn" is a very weak flex.
The first Smalltalk-80 book you randomly find is 560 pages.
Also, there is a weird bargaining with "but not block temporaries" and "not an instance variable". Why not? Half of the postcard is basically empty. Also, "except primitives" — how many primitives are there?
Next up: “all the characters you need fit on a single keyboard!”
The appeal of having a very simple, base syntax and almost everything in the library / primitives, would be that code is always easy to read and write, also on the 'reflection' level, where most languages have specific keywords that cannot be used 'first class' with the rest of the language. E.g: Types next to class objects or operator overloading, look at Swift.. (Of course the complexity of a full working system (library) does not disappear in Smalltalk, it's just easier to read and modify. :)