Marriage books are one of the special requirements that have a husband and wife must have to avoid problems when something very unwanted happens, such as a raid when a legitimate couple stays both in a hotel room or when they are both in quiet places.
When a couple of a different sex is caught somewhere quiet or when entering a hotel that has strict rules, but they cannot show proof of marriage in the form of a marriage book, this will cause them to be in big trouble or will be rejected by the hotel for stay even though they have claimed to be a legitimate couple.
Therefore, it is very important for couples to have these requirements to avoid cruel accusations and the like, without being able to show proof of marriage in the form of a book, of course people will not believe that they are indeed a married couple.
The marriage book seems to be very normal and does not change like a normal book, but the benefits are enormous to prove a good bond without human prejudice happening.
Thank you.