Read the article, then read comment #3, by the author:
You do have to keep the wings level with rudder or aileron.
This means that you have to be able to keep the wings level to start with. So in a spin, you've got to recover from the spin first anyway. And in IMC, you are now trying to keep the wings level on instruments while the aircraft is bucking every which way. (Assuming that the instruments work in the first place - if you have an engine failure in IMC you also lose vacuum pressure and thus the AH and DI.)
I like the DA40 but to suggest that this parachute mode is a direct contender to the Cirrus CAPS system is a bit over the top, I think.