I use C&S for convenience.  I post my items the same day (provided the transaction is complete before 5pm)   I can do that because I do not have to travel to the PO.

I had a buyer claiming non-delivery but I was able to prove it was delivered and signed for (who signed it and what time)  Turned out it was a relative who forgot to inform the buyer.  In case of the parcel actually going missing, I would have refunded the buyer and chased it up with Australia Post.

If for some reason a parcel goes missing and no tracking can be found and Australia Post refuses to compensate, then I will stop using C&S.  It would defeat the purpose  what I use it for.