Only for a smaller niche of commercial photography - the one that sells large fine art prints. You don't really need high resolution for billboards or posters -

Only for a smaller niche of commercial photography - the one that sells large fine art prints. You don't really need high resolution for billboards or posters - they are viewed from large distances. Magazines are not printed with that great quality. Even high quality photo books are more than fine with 20-30 megapixel shots.