/var/www/clients/clientX/webY/tmp why has 777 permission

Hello
after ran the following command to find full permission files
find / -xdev -type d \( -perm -0002 -a ! -perm -1000 \) -print
I've found for example the ispconfig websites directories with full permissions as bellow
/var/www/clients/client"X"/web"Y"/tmp
Is it necessary indeed?