I think www can be useful offline. We here all recognize domain.tld as a website, but I suspect that www.domain.tld is more recognizable to non-technical folks. "Visit www.domain.tld for more information." etc.
Agreed - if it's a site aimed at a non-technical audience I put it on www. and 301 domain.tld to www. And the other way round for sites aimed at a more technical audience.
