When and Why do we need to use "reboot=" parameter?

Issue

1 When do we need to use "reboot=" parameter?

2 Is man information of "reboot=" correct?

According to man bootparam

reboot=[warm|cold][,[bios|hard]]'
           (Only when CONFIG_BUGi386 is defined.)  Since 2.0.22 a reboot is
           by  default  a  cold  reboot.  One asks for the old default with
           'reboot=warm'.  (A cold reboot may be required to reset  certain
           hardware,  but  might  destroy  not  yet  written data in a disk
           cache.  A warm reboot may be faster.)  By default  a  reboot  is
           hard,  by asking the keyboard controller to pulse the reset line
           low, but there is at least one type of  motherboard  where  that
           doesn't  work.   The  option  'reboot=bios'  will  instead  jump
           through the BIOS.

Do We need to concern about "(Only when CONFIG_BUGi386 is defined.)" ?