You can lose mobile access less than an hour or so out from town!
If you work in the regional or country Queensland or you are in the 4WD heading to FNQ, Emerald or Sapphire prospecting or to any of our great national parks or further afield then a satellite phone could save your life. (Perhaps just to keep in the good books with the folks at home)
If fishing is your passion chasing tailor at your secret spot or hunting big reds behind Fraser Island or just cruising further out from the Great barrier Reef then help can be a long time away.
Australia has only 27% mobile coverage so don't count on your mobile phone away from the main drag in Queensland! (That does't include out territorial waters)