No, you won't need to add your phone number to play Scars of Honor.
We added this option for the people who want to be absolutely up to date with the project. We are gathering phone numbers in order to send announcements, offers and important notifications in the near future, you won't be bombarded with messages that I assure you. If you don't want to add your number, you have the right and freedom to not add it.
No one is spying or tracking your (from our side that is), we don't have that intentions or technology so don't worry.
I appreciate the response and Beast Burst respecting it's customers privacy. It's rare to find this level of integrity among businesses today.