Its notability is in that it existed well before Google's Go, and so latter would've been better off selecting a different name.
So why again should Google make the name change?
If the 'Go!' creators had any hope for using that name on a series of offerings (tools, books, etc.), they have to object to Google's use, to retain the presumptive rights they'd established so far via use.
Notably, the word 'bang' does not appear in the book, "Let's Go!", so it is unlikely to be the author's preferred pronunciation: