the following config is in the C891F-K9 in a production network my Question is why they config the ip nat static with route-map option
router#sh running-config interface g8
Building configuration...
Current configuration : 357 bytes
!
interface GigabitEthernet8
description WAN
bandwidth 512
bandwidth receive 3000
ip address x.x.x.x 255.255.255.248
ip access-group BLOCK_RECURSIVE in
ip nat outside
ip ips myips in
ip virtual-reassembly in
zone-member security INTERNET-ZONE
duplex auto
speed auto
crypto map primarymap
service-policy output MP_STD_4QUEUE
end
ip nat inside source static 10.1.1.1 10.87.11.11 route-map NAT_MAP
route-map NAT_MAP permit 10
match ip address NAT_LIST
match interface GigabitEthernet8
ip access-list extended NAT_LIST
deny ip 10.0.0.0 0.255.255.255 168.182.0.0 0.0.255.255
deny ip 10.0.0.128 0.255.255.63 any
permit ip 10.0.0.0 0.255.255.255 any