Hell, you can call it 64bit if you want but nothing can resolve 64bits or 32bits for that matter (dunno, maybe at 0K you can, but that is damn cold). These are "marketing bits."
no, I don't think this is marketing. Any ADC or DAC has ENOB lower than it's bit width.
This is because ENOB and SNR depends on jitter, linearity, noise and many other things.
Which for real ADC/DAC will never be the same as for theoretical ideal ADC/DAC.
Real DAC/ADC always will be a little worse than theoretical ideal DAC/ADC.
For real DAC/ADC there always will be some jitter, non-linearity, noise and other stuff, which will leads to SNR degradation.
But these bits are fair.
Just check, you will not be able to get SNR=140 dB on any of existing 24 bit DAC.
But this 32 bit DAC provides SNR=140 dB.