I suspect that 192k vorbis and 128k opus would also be transparent for you as well (unless you listen to techno/industrial and have really good speakers). Might save you a bit of space.
Yeah that's likely true. I had chosen MP3 for reasons of total compatability and 'good enough' compression, but it seems like almost all music players have good support for those formats as well. Maybe at some point I'll switch over.
MP3 also has some fundamental problems when dealing with short sharp sounds (e.g. castanets), which have been fixed in subsequent audio codec generations such as AAC, Vorbis or Opus.