Preaching to the converted here: for me role-playing is all about creating an altenate reality and populating it with believable characters that 'come alive' within the context of that shared alternate reality... and so of course I applaud any effort to make that task easier.
Some of it seems banal, and I do question the wisdom of suggesting that you answer questions about the character you are creating out-of-character rather than in-character. If nothing else, when I'm creating a character the easiest way for me to find out what he's like beyond numbers in a stat block is to channel him and find out what he's got to say. It can also be regarded as an on-going process, I often get to know a character properly as I play him, rather than have him spring to life fully-formed from the outset.
However, the concept of using a string of questions to ferret out what a character is like as a person is sound; and the questions chosen do a good job of empowering you to look at some of the fundamental things that make him tick.
Then things get a bit tangled, as there is a section - which SHOULD stay out-of-character - about what you, as a player, are looking for from the game for which you are preparing the character. Useful information for the GM, to be sure, but something to keep apart from who that character is and what he is like.
Ultimately, the more you know about your character, the better you will be able to play him. Try to internalise as much as possible - when your instinctive response turns out, when you think about it later, to be bound up in the personality and background you've devised for him, you'll know you're getting it right.
A useful little tool to help you think about who 'you' are in the shared alternate reality you are about to inhabit.