Yes, The plugin suddenly stopped not only in Opera but in all devices. The app crashes suddenly and I got a news that google is upgrading the hangout so that people can take more advantage of it. The problem was from the backend side only and now the problem has been fixed by the developers it is working normally. You can also update your opera browser and install the new version. The given article will help you to understand the benefits of Google Hangout more.
https://onmogul.com/stories/benefits-of-google-hangout