From CSS to F5 snat clarification

Having taken over a project to replace our inline CSS with an F5, I can see on the CSS snat is being used on every VIP. Am I correct in saying snat is not needed when the load balancer is inline? It’s confusing me why it is configured on the CSS, I know it is needed in one arm mode. So In my case with the F5 being the default gateway for the servers the VIP would look like this (converted from CSS with snat).

Comments / clarification welcome.

Thanks.

pool LoadTest_IIS {

monitor all status-html

lb method least conn

member 10.61.4.2:80

member 10.61.4.1:80

}

virtual LoadTest_IIS {

pool LoadTest_IIS_LoadTest-Catchall

destination 10.61.101.100:80

profiles {

tcp {}

}

snat automap

persist source_addr

}