It was not the media’s idea. It was Trump’s.
Trump has been doing pretty well running his campaign so far. It would be inconsistent for Trump to come up with an idea that is counterproductive to his overall goals, which of course including winning the nomination and the general election.
Trump debates Sanders, treats him with respect although disagreeing with his politics completely. The proceeds go to a women's organization. This has the following effect: breaking Sanders' people off from Hillary, who they despise anyway, and who will, as it looks like now, compound the dislike by bulling her way to the Democrat nomination. Sanders' people, or at least some of them, to Trump. In addition, Hillary's "War on Women" accusation against Trump is disarmed completely by 10 million buckadingdongs to a women's fund. And Hillary has already overused that attack and her support among women is very shaky at the moment. Some of them - not all, but enough - to Trump as well, and Hillary's best attack thwarted.
What's he out? A debate against an aging socialist with the utter failure of socialism in Venezuela undeniable - Bernie has already desperately dodged comment on that issue. Trump wins gracefully, he's holding all the cards. And mind you, Trump only has to threaten to do all of this for it to work. He still gets to decide whether actually to pull the trigger or let it simmer.
Nicely played, IMHO. But then I'm only an amateur at this...