While I think it is good for both Germany and students, it probably has a bit of geopolitics mixed in. All those young people, if they return to their home countries, will be naturally more oriented toward German products thus indirectly making German economy stronger. I saw a similar theme in Russia, where there is even a specialized university for this [1]
[1] https://en.wikipedia.org/wiki/Peoples%27_Friendship_Universi...