I forgot about the "duo socket" marketing concept from Grey Pneumatic; after looking at their catalog for this tool line, it does seem that your extension is even shown in the cat being used with a impact. One tool for regular use and impact usage, ..... hmmm!
http://fileresource.sitepro.com/fil.../792/03BA679B-8165-3691-E0D2-F2C55951EB7B.pdf
One thing I've noticed; if you get a "multipurpose" tool that is supposed to do "everything"; there is always sacrifices that have to be made. As the old saying goes; "somethings gotta give". These types of tools in the worst case scenario; don't do anything particularly well. It looks to me in this case, that the wobble indention; is pretty thin for the stress of a impact wrench. A universal style impact attachment; would be more suited for air tools and actually be able to handle the abuse. If you put the wobble at a extreme angle; I don't think it would be able to do much but break under that kind of stress/binding, its just not made to handle this, imho. Just like any tool; real world usage typically, will shake out the weaknesses and you just found out what the extension can or cannot do.
What is the primary difference between impact and chrome sockets? One major difference is that impacts are typically thicker and stronger; while the chrome are thinner and weaker! Well, finding a middle ground without sacrificing strength; thats a hard middle ground to find! The composition of the metal; where it can take the abuse of the impacting and provide enough strength, be thin for tight areas.... that might be a tough requirement to fill! I'm just not convinced a wobble socket is suited to air impact abuse! There is a reason that regular chrome and impact sockets are sold; each has their own role to play, in different situations!