Isn't the question really that the chance of the aircraft crashing is statistically quantified and acceptably small where the risk of the package not being a normal mobile phone is also quantifiable, staggeringly small and completely ignored in the current thinking.
Every point about the potential to harm is true but the odds are staggeringly small and unlikely. Like the 95 year old woman who had her incontinence pants examined by the TSA last week as they were taking no chances. It's really difficult to argue against that mantra that to do anything else is taking risks with people's lives, even decades after Lockerbie where bombproof cargo containers are still not widely used due to a risk vs cost analysis.