If you are aiming for industry job then learning NMR will be very helpful. Moreover, 'Metabolomics' is the next big omic and NMR is quite useful in metabolomics research.

There is no harm in learning anything. You never know, it may come in handy in the future.

I agree with Anna. Never lose a chance to learn something new. In biology, you never know what you will work on in a couple of years. Even if your future projects will not require NMR it still gives you certain advantages: (i) since very old times, a good physical thinking helped biologists to discover new things and not to do stupid mistakes when interpreting nature (remember F. Crick, for instance, he was a physicist originally), (ii) your CV will look much more attractive to your potential employers, (iii) as Abdullah pointed out, NMR is a powerful technique which is widely used in numerous research branches, so it is unlikely to stay without application. Good luck!