Attention Helldivers, Due to technical issues at the launch of HELLDIVERS™ 2, we allowed the linking requirements for Steam accounts to a PlayStation Network account to be temporarily optional. That grace period will now expire. See details below in this post. Account linking plays a critical role in protecting our players and upholding the values of safety and security provided on PlayStation and PlayStation Studios games.
If you make a PSN account you have to agree to their ToS, which probably lets them do more than a EULA does.
It also boosts user numbers, which looks good on paper.