Actually it matters very, very much. Not because of the actual ATAR- I don't care what others get as long as they do their best because everyone has different levels of natural ability etc. At the end of the day, if you reach your potential, that's all you can do and you should be proud. The reason why it matters is because he has lied about it multiple times which tells me he is either one of a few things:
1) He is insecure about himself and his ATAR -> would not want to hire
2) He just lies -> Would not want to higher
Basically, the crux is that yes, a person who is well rounded WILL get hired over a basement. My dad has interviewed hundreds of people and yes, they definitely won't hire those who can't connect with people etc. BUT, you can't just say that high ATAR=basement/no social life. I know people who are expecting 99.7+ ATAR's and have very well developed social lives, sporting commitments etc.
And Solo- I'm noticing a lot of jealousy in your posts...
I would definitely associate leaving an exam with 1.5 hours to go as "not trying your best". Firstly, you shouldn't even be able to finish a HSC bio exam in 1.5 hours but even assuming you did, I guarantee you in 1.5 hours you could have found things to improve -> check MC, draw diagrams, check expression, clarify stuff etc.