Drivers are software that interfaces a PC or mac to support a device that it is written for!
Firmware is the machine codes that operate whole pcb or programmable chips!
Yes, you may need external device and/or programs to load firmware.
Yes, firmware must be loaded in accordance to the steps outlined. Otherwise like I said: expensive excercise.
Reason for firmware upgrades is to correct faults that were not detected during testing before production or faults that are reported by the end user that cannot be fixed through existing settings or replacement of hardware. Drivers are also subjected to these senarios in which the versions are updated.
Not every driver/firmware update will fix issues 100% of the time, infact sometimes the updates can introduce different faults so be warned!!! Like I said in some items you do not update unless it is vital to do so!!!