It shouldn't be taken as scientific truth but it can help you know yourself and others better, and it's an insult to compare it to astrology because at least it's not based on completely random things like the position of the planets when you were born. The issue is that most people only know MBTI as online tests, which are self-report and have extremely vague and stereotypical questions that can very easily be manipulated to get whatever result you want, with the worst offender being the most popular one, 16personalities, which isn't even an actual MBTI test but a BIg 5 one (which is not to say Big 5 is bad, but it's very misleading to map it to MBTI types). In reality to use MBTI somewhat effectively is going to take studying Carl Jung's work, how MBTI builds on that, lots of introspection, asking people about yourself, and lots of doubting and double checking your thinking. And very importantly you have to accept that in the end this all isn't real and just a way to conceptualize different aspects of our personalities and it's in no way predictive, you have to let go of stereotypes, anyone can act in any way, it's just about tendencies.