Yes, I think it should be considered a virtue. It's a very useful skill that I used daily. It shouldn't be beaten into kids ("learn your timestables!!" is not

Yes, I think it should be considered a virtue. It's a very useful skill that I used daily. It shouldn't be beaten into kids ("learn your timestables!!" is not an effective teaching method), but if using an abacus or similar helps people calculate faster, it is likely a good thing.