It is highly likely that the above-mentioned three newsletters are from a parent company, which are distributed through different channels. It can be used to gather essential pieces of information that might look safe in the user’s eyes. However, this can be misused to sell personal information to carry out identity theft. It might further ask the user for the date of birth for the activation of the fourth newsletter.
In many scenarios, questions that involve personal details are unnecessary, and you should not provide them to any random person, company, or website unless it is for a legitimate purpose.