. One concern I also have would be the AP staff knows there are goods in it paid by someone because it has the ebay logo on it, whereas the Parcel Post Plus satchels dont

Every parcel has something that somebody paid for.  Or what do you think people send to each other; worthless bits of junk?

Even if AP does not compensate for lost C&S satchels, I am sure it is much less likely that people will do false claims if the tracking shows it was delivered.  I cannot see any reason why people do not use them.  I use them for anything cheap that is too big to be sent as a letter.  If it has to go as a parcel it may as well go with the C&S tracking.

Nothing will ever be 100% safe, and occassional loss has to be factured into pricing of the under $50 items.  That is the down side of on line trading.