I agree, you shouldn't rely on others to make your own decisions. It's your choice how you spend a bit of your money for your own enjoyment. No one should be a voice of reason for your decision-making besides yourself.
I agree with you that there is no reason to rely on other's predictions either on sportsbooks or on casinos. There is no reason to rely upon casinos but for sportsbook, we may take help information on Google, FIFA website countries website for the team for cricket, and ICC's website and countries website for Cricket, and the same for others. Also, we may research on Google.