Imagine the sequence with that field where it set down, with some high-tension power lines in the background. At least with an auto, you have a little control over where you're going to set down. With a parachute, you're at the mercy of the wind.
A ballistic parachute is a reasonable option for single-engine Cirrus planes, because the alternative is finding a big patch of open area to glide into. Not always easy in built-up areas, hostile terrain, or open water ditching at speed. On a helicopter, maybe not so much. Plus the added weight, aerodynamic drag, and risk of accidental deployment. I think it would have to be a purpose-built design, like a "safe Robby" for the entry-level private owner with some bucks to spend (like Cirrus).