User blog comment:TwilightReaderFan/Season 5 Finale/@comment-7600752-20151001173312/@comment-5014364-20151001195038

Oh...well it's not like how the "True Blood" novel series is drastically different from the television adaptation, but due to their sheer size, the Game of Thrones television series had to cut quite a bit out - somewhat more than Harry Potter or Lord of the Rings.

Short answer to the entire conversation; YES it is worth spending the time to read the novels. Even the "accurately adapted" parts of the novels are merely summations of the longer stuff in the novels. Not even getting into changes. You gain vastly more by reading them.