No, it is not only about scaling or gluing different languages. Some other aspects that microservices can help with:

Reliability. There is a chance that one microservice crash looping does not bring the whole system down. This would not be an advantage if languages were better at isolating failures but they aren't.

Independent release cycles. It is good to be able to upgrade only one service. For example if something goes wrong, you roll back only one service. You also have a smaller code base to debug.

Runaway resource consumption. A memory leak or a logs explosion only affects one service. This arguably is a version of "scales independently".

Above stuff is from my experience at Google. YMMV. I can imagine that a badly designed microservice architecture does not bring these benefits.