It's not like there are only two buckets:

1. HFT doing ass-simple arbitrage where only latency matters 2. More sophisticated slower trading taking in deeper signals

Those are two points along a continuum. If you are reacting to an earnings announcement by having an LLM read the earnings release and listen to the call, getting the results a few seconds earlier lets you get your trade in a few seconds earlier. Just because "not HFT" doesn't mean "completely latency insensitive".