You are correct. BUT, it's not always about speed. Being able to ride in really crappy conditions and not having my FW sound and feel like someone poured sand into it is where the value of a WI FW really comes into play. That, and serviceabillty.

I bought an ACS crossfire to use on my CX/gravel wheels and all it took was one long, wet and gritty ride and it was effectively toast. I was able to drown it in WD40, blow it out with comrpessed air as best I could and flood it with oil again to make it sorta 'rideable' again but you can bypass that problem entirely with a WI.