Yes, this is a marketing/PR strategy well known. Cessna's electric 172 program was (IMO) one of these. The Airbus has more of a track record with electric, having actually built and flown at least 2 planes. As you said the Sikorsky, and the 172, never flew. Airbus claims the E-Fan is being marketed as a trainer, given its one hour flight time that seems reasonable. But I'll leave it to your discernment to decide if you think the Airbus electric is just a "green" marketing strategy.Quite a few giant companies build electric prototypes just for "green" advertising, even at loss.
Bob Lutz, the retired GM exec explanined this in his book. His GM Chevy Volt was not expected to make a profit.
I saw a Sikorsky electric helicopter shown at Oshkosh that never flew, quietly shelved. Same for Cessna, Boeing etc.