I don't think it should be retired, saving space is still a good thing to be efficient for some circumstances.
For anyone curious about the difference if you set a VBR and CBR at the same value like let's say 20, you can have a higher maximum bitrate on VBR that allows the average bitrate to exceed what it would normally be stuck at in CBR which is 20, such as in super complicated and detailed frames you could allow it to go up 25, and then go lower than its average bitrate in parts where it doesn't need much bitrate like down to 15. Whereas CBR just is constant the whole way through even when it doesn't need that higher bitrate. Plus with 2-pass VBR it's even more effective.
Now of course if size isn't an issue, you could just set your CBR at 25 or whatever and have that quality the whole way through, plus it encodes quicker, so it's definitely good too and sometimes better to use.