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Why do bike companies offer carbon, aluminum and steel track forks if weight does not matter?
Because customers think that weight matters :-)
Carbon (done properly) is stiffer, stronger and lighter than the others. These are all good things, in that order. It's also more expensive, which makes room for steel and aluminium further down market.
Some people offer "track" forks with no brake hole. This is pretty pointless, as the brake hole is doing no harm if you don't use it, and having it there makes it much easier to ride your track bike on the road should you so desire.
A few people with old-fashioned frame geometry offer "track" forks with less offset to provide reasonable trail in the face of steep head angles. This is fine if you're stuck with one of those frames.
I hadn't even started on why he thinks light weight is an attribute to chase in a track fork, or why he thinks there is even such a thing as a track fork now that most track frames share geometry with their road cousins.