The clear distinction to make is that the governments "claimed" by the Soviet Union following the Second World War (Great Patriotic War) were their own separate governments that had political ties that waxed and waned during the Cold War till the end when majority broke free from communism and thus the pressure of Moscow. This fact tends to dissolve when discussing the Eastern Bloc. That being said there was some inherent benefits to being incorporated within the Soviet sphere of influence.

The major one being trade with other Eastern Bloc countries and the Soviet Union. On top of trade between "member" countries, with restrictions, there was a military benefit as well. The basic idea is that the Soviet Union would defend other communist countries in the region. This is pretty standard fair for typical trade and military alliances. The Soviet Union sought to create a buffer zone from the West in case of another round of World War sprouted, it did this by aligning these other countries in Military and Economic alliances through local communist governments. It also lead a benefit to the Eastern Bloc country's governments by protecting them by suppressing uprisings through military force.

The other benefits would be economics within the countries, which is a better discussion for Political Sciences; mainly the benefits to workers, education, and the similar that are inherent in a communist system.

This is obviously not mentioning the suffering the countries people felt throughout this period, and I am not going to discuss it because it would be a tangent from the original question.

Edit Note: I did not include the territories directly part of the Soviet Union, who by contrast had a lot of direct investment into their respective countries, such as Kazakhstan and Ukraine, where the Soviet Union sought to industrialize and bring up through economic growth. The answer deals directly to the Eastern Bloc countries, as asked by the original poster.