I'm less concerned about jersey sales, they're bound to increase, but for casual viewers it makes the viewing experience much much, much more easier to watch, surely every one of us has gone through scenarios of watching origin or another sport and fellow casuals identify players right away with their names, brings more context to what's happening, familiarity with individuals. Or with myself, I realise players easier when watching the champions league, watching a German team v Spanish team when I only follow the premier league. And I'd be like "oh that's Bobabc, I've heard about him, in the news, social media, my team wanted him, etc etc"
It's just something that needs to be done, and I believe back sponsorship wont lose, if anything, it adds value to the back sponsorship even if smaller placement, like Warburton mentioned.