I couldn't care less what's written in my astral chart. I set my life the way I see fit, not believing in "fate" gives it less power as well.
A natal chart (not astral) is not the same as "fate". Your entire life, personality, future, behavior, major events that happened, are happening or will happen, how your life is going to play out regarding work/career, finances, love, health, all of these are more or less "modeled" in our charts and will play out a certain way irrespective of how much we believe or disbelieve in them or irrespective of the importance we give to our chart. The only way this can be changed if by countering negative energies with spiritual workings (positive energies). A natal chart is basically the totality of all planetary energies that were at the moment of our births and which will influence our lives based on the relation between each other and how the energy of every planet manifests. The reason this is happening is that planets are giant "objects" that possess proportionally giant "amounts" of energies that affect matter and "small living beings" like us. I would suspect the specific energies of each planet come from their physical structures as all planets are different, exactly in the same way certain precious and semi-precious rocks on Earth naturally contain different types of energies and can be used for various purposes. I am not sure what is the non-physical aspect of the above, but there most likely is one. Imagine for example that your bless your house with so much energy for peace that there will be no conflicts in your house for decades. Planetary energies work in this way to an extent, their energies are so powerful that they manifest certain events etc. But the difference is that planets do this naturally, and nature is chaotic. Life and death, destruction and creation, peace and cruelty are all aspects of nature and existence which manifest both in the most brutal and savage ways or in the most beautiful or peaceful ways, or anything in between.
Because some people (astrologers) know what are the energies of each planet and how they manifest in each zodiacal sign, and how they interfere with the energies of other planets whenever they "intersect", predictions can be made about future events, people's behavior can be explained based on these energies etc., extremely accurately. Astrology is the science of explaining and predicting various aspects of existence based on the planetary energies that influence them. In order to understand how your life will play out you may want to care about what is written in your chart, because in this way you can take spiritual (and physical if necessary) action to mitigate potential disasters that could strike at a certain point in your life, because if you don't know your chart you will never have a clue about how your future will play out. Not giving importance to this is not going to reduce the chances of potential negative events to occur, even the opposite, it will leave you completely exposed to whatever is going to happen, good or bad. To give a hypothetical example, if you could predict that you will encounter financial difficulties later in life, or if an astrologer could predict this by doing a reading of your chart, then you will have enough time to prepare and be mindful of your finances. This is one example but "fate" is chaotic, it can be anything, you never know until you are willing to find out and prepare for it. I remember reading sermons from HPS Maxine who warned people around her about disasters that she saw from their charts. This was either on her forum posts or in her
sermons page on the JoS site, I don't recall exactly as it was a few years ago.
You can read about astrology from JoS, generate a natal chart (it will be more accurate if you know the hour and minute of your birth beside the day) and then compare the placements you see in there with the description of each placement from JoS, you might be shocked. (however you are unlikely to find extremely accurate information about yourself this way if you are not professional in astrology)