I think this ad is fairly inoffensive in that it's not really pushing it's point on you and the overall message is a positive one i.e. enjoy your life.
This is not seriously going to convert a person of strong faith and if their faith is strong, why should it offend them, they should dismiss it off-hand as nonsense. The message is obviously targeted at those who are sitting on the fence. I know people who aren't sure about God for various reasons but because of social pressures or their upbringing they are made to feel guilty about their lack of religious faith, why should they.
I would be equally OK with an add saying "Jesus can save you, be happy.", but I'm not OK with, "join religion X or you will burn in hell".
To the person who said, "why are they advertising, they don't need to raise money for a church", you know there are people who spread the word of God for altruistic purposes, why can't this be the same? If you genuinely believed you had the key to happiness, wouldn't you share it?
