Not solely. Opus is a hybrid of the SILK codec, which is more for speech, and CELT, which is more aimed at music. It can seamlessly switch between the two methods and use them simultaneously:
https://wiki.xiph.org/OpusFAQ#Why_not_keep_the_SILK_and_CELT...The main goal was streaming (of both music and speech), and hence, low latency. Matching or bettering high-latency codecs (like Vorbis) on quality was just a bonus, and I believe somewhat of a surprise to the developers when listening test results came out.
