I assume this is required for some of the features that we have for SMD <-> Discord linking. Probably to ensure that you're actually in the StarMade discord before it tries to assign roles to your account. The feature itself is not developed by us:
Discord Integration
This data is sent only to SMD, not any third parties. I'll have to check to see exactly why "Access your email" and "Know what servers you're in" are required, although I have a fairly good idea already.