Some people keep both lossless and lossy copies around. It makes sense to have lossless backups on a cheap storage medium, and only carry around lossy versions

Some people keep both lossless and lossy copies around. It makes sense to have lossless backups on a cheap storage medium, and only carry around lossy versions on your phone. And switching to Opus for your lossy version would make a lot of sense if you're currently using an inferior format.