And that is a totally different thing. But you can’t cite a book of stories ABOUT Jesus to prove his existence, any more than citing any other set of stories proves the existence of the characters in those stories independently of other sources.
Christians too often get into the circular reasoning of it’s true because it’s in the Bible and we know the Bible is true because it says so. That’s not an argument that is going to convince anyone else.
Of course--I've already granted your very sensible argument and moved on to the real crux (ahem) of the matter. Habermas is only arguing the strength of the first Christians' belief, which upon recent examination becomes more and more impressive--so much so that atheist scholars now grant it was substantively based, by eyewitnesses. So, it is indirect evidence of Jesus existence and resurrection so powerful it has convinced the most skeptical audience.
Ultimately, it always comes down to a very personal belief. After all, even if we had video documentaries depicting Jesus' earthly sojourn, they are subject to counterfeiting. Jesus' existence since then has been (somewhat) debatable, as He intended: "...blessed are those who have not seen and yet have believed." (John 20:29) But during the coming Millennium, when He is ruling in person for all to see, no one will be able to deny His existence, His resurrection, or His deity.
The question then for everyone born during the Millennium will come down flatly, as it should, to the straightforward question: whether one will trust Him eternally, or not.