A continuous Global pass would allow you unlimited travel across Europe throughout your stay, but require some reservations on high speed trains. It is ideal for those with plans to wander freely across Europe.
The 49 euro monthly pass will allow unlimited travel on all German regional trains and most buses and city transport. So they complement each other with the overlap of German regional trains.
The 3 month pass cost about 770 euro so would only be worthwhile if you intend a lot of weekends exploring Europe on long distance trains, otherwise, as well as the proposed monthly pass, most German states have a range of passes.
A bit of research on your aspirations and your budget will no doubt show you the best way forward.