My vague recollection of the relevant bits of the C standard has it that there are a few differences between how pointers to void, pointers to char, and pointers to anything else are treated in some respects. This might be one of them.

"A pointer is a piece of memory/register that contains an address, and an address is just a bit pattern."

This is true on virtually every modern system, but (if memory serves) not literally every system ever, and the C standard leaves room for some surprising things in some places. It would have been very nice if the author had actually included some references, though.