The authors of the article I linked point to the risks of hyperinsulinemia to the lung from ANY source, not just inhalation. Superimpose that risk on lungs already impaired by diabetes:
"Diabetes is associated with a significant impaired pulmonary function in a restrictive pattern as compared to non diabetics. The pulmonary function impairment was found to be more marked with diabetic duration especially after 10 years. Subjects with type I diabetes had lower FVC and FEV1/FVC% than predicted; it could be related to poor glycemic control."
As far as "it does not stay in your body as long as other insulin," that potentially INCREASES the risk because of hyperglycemia due to late digesting carbs requiring additional doses. Consider someone like "Gustavo Basualdo" who was mentioned above. He tweeted that controlling his glucose requires TWELVE cartridges a day! Even if he's using just the 4U cartridge, that's 48U inhaled every day. He uses in ONE day what would last a typical type 1 on lispro a WEEK or more. And that is WITH regular exercise -- at least that's what he claims.
Then open the afrezza insert and look at page 15 and note that the concentration of insulin in the blood reaches 2-3 TIMES that of lispro with each dose. Note what the insert also says:
"AFREZZA provided less HbA1c reduction than insulin aspart, and the difference was statistically significant. More subjects in the insulin aspart group achieved the HbA1c target of ≤7%"
So TWELVE times a day "Gustavo Basualdo" spikes his insulin levels into the stratosphere, risking his lungs and who knows what else -- since the safety study hasn't even started -- and he can't even expect to achieve an A1c that he could get from lispro? Does that really make sense?