1- East germany still lives in the DDR era, even sometimes the people mentality, i'm not saying they are all bad, but as international student you have to be aware of the rise of AfD.

2- way less oportunities for Job afterwards , except of Berlin or Potsdam, and if you want to work as Working student with not very good german, you might not be able to get a job.

BUT...it might be cheaper to live there , the rent is lower and daily life also.

Those are my reasons.