Time to Log......????

Pr
Y'all know the thing of when you have to log bout everyday (of about how you feel, did you have sex, what you craving..., Etc.), I guess, but I don't see the purpose.... Like in the beginning I used to log everytime, but I'd like to know what the reason for logging, or how does it help more in my period?? 
And I know those might be some dumb questions but it's just something that we all got to know what it's for since we all have this all have this app..., And I guess logging is recommended too😶🤷🏻‍♀️🤷🏻‍♀️, not sure but, help me bump up my knowledge😅😅 girls, please and thank you😁💕