If temperature is used to kill the baddies, then why the different "safe" temperature requirements?

Pasturizing fluids to use immediately 160 degrees or so.
Boiling fluids / water bath canning 212 degrees or so.
Pressure canning high acid foods 240 degrees or so.
Low acid veggie canning - commercial 250 degrees or so.

Should cooking thermometers be part of our BOB or Bug-in kits?