Digital signage ads provide a better return than TV

Bill Gerba explains return (ROI) on Digital Signage. If we have a good content channel, good marketing strategy... we can have a good ad strategy

"So what does it all mean? Simply put, if we assume that my estimate above isn't wildly off the mark (and it might be), then for every dollar that comes out of TV advertising and gets put into digital signage advertising, a CPG advertiser would "recover" the entire $0.51 loss and then generate a small profit on the original amount spent. (This is based on an average return of $1.08 for digital signage versus $0.49 with TV, each on a per-dollar basis.) For an advertiser that spends $10M a year on TV, simply moving 10% of that into digital signs would be like reducing their ad budget by $590,000 without sacrificing performance. In fact, there would probably be a performance boost, since their skills with designing and deploying ads for digital out-of-home environments would improve with experience. If we extend this trend to the advertising industry as a whole, moving 10% of TV ad spend into digital signage would save $4.5B per year, with no loss of performance and lots of upside potential.
All else equal, will a spot on a digital signage network "do" more than a spot running on TV? And where does the bulk of an in-store ad's value come from: "hard" sources like sales lift, or "soft" sources like brand recognition?