I think it can be interchangeable, depending on where and who you are. As someone who's lived in Nullsec a few times before, it's definitely used as intel more often than not, chat tends to happen more in corp, some in alliance but fc's tend to get shouty if chat is going on in alliance. Or at least they used to.
But as for local in Null you look at who is and isn't blue and you report it in actual intel channels along with what ship you see them in, most of the time people are just passing through but for when they're not, any little piece of information you can gather from just local chat could be crucial to taking care of problems quickly.
As for low-sec I don't think it's as prevalent, perhaps with the exception of care-bear corps it's more a "How many targets are around" and, uh definitely NOT a trolling opportunity for roaming hunters like myself, innocent whistling ensues. Like I said, it's interchangeable on a "who and where" basis.
