Joan Murray would have to say yes.
Wow. Any comments from Joan as to which hurt more, the crash to earth, or being eaten by the ants?
That would certainly be what is known as having a Very Bad Day.
Yow. Ya gotta be *reeeaaaal * careful how ya phrase things around here. Yeah, I guess I know the bit about subjective value judgements made by humans (who else?). I didn’t really mean to imply that. I actually meant that I thought the OP was just looking to understand a little something more about the ecofunction of fireants so that he could easier accept their presence in his surroundings. Thougt Colibri might enlighten us in that specific arena.
*"As Mr. McGehee walked through one of his pastures on Wednesday, grasshoppers leapt up like popcorn popping around his feet. Chiggers, a tiny biting mite, have exploded. “I caught a calf the other day that had ear ticks,” he said. “I hadn’t seen ear ticks in 30 years.” *
I will e-mail this tidbit to Mrs. J., who still misses Texas. 
That wasn’t primarily directed at you, it was in reference to the OP as well. There is no way to discuss how fire ants might be “valuable to the ecosystem” unless you specify what you consider to be “valuable.” Some ecosystems have high diversity, some have high productivity, some have high standing biomass. These may not only not be correlated, they may be mutually inconsistent.
The thing is, the ecology of fire ants in North America, where they are not native, is quite different from their natural ecology in South America, where they are originally from. In the US they reach far higher densities and much larger colony sizes than they do in South America, presumably due to the absence of their natural predators and parasites (most notably a kind of parasitic fly). Fire ants in the US are essentially pathological relative to how they behave in their native range. Unfortunately, information on the web is so dominated by sites about controlling introduced fire ants it’s difficult to find much about their natural ecology (which is not all that well known in any case).
In my book, fire ants have no redeeming ecological value in places where they are introduced. Whatever they do is probably detrimental compared to the original ecosystem. While they may have some small benefits, such as recycling nutrients or controlling ear ticks, these may not be accomplished as well as they were by the native fauna, and in any case are slight compared to the overall detrimental effects.
Fire ants are just one kind of payback for messing around with Mother Nature.
After the fall of man, they were proselyted by satan, hence the name “Fire Ants” and their nasty habit of biting.
Wait a minute, now. Fair’s fair. If the OP has to define “beneficial,” then you have to define “detrimental.”
Animals have always migrated into new environments with varying results. Granted, humans have accelerated that process by letting other animals hitch a ride from one ecosystem to another, but fire ants probably would have made it here sooner or later with or without human help. It’s not as if there are impregnable obstacles between South America and the southern US.
True. I let myself get a little carried away. I was putting a value on diversity and integrity of the native fauna. Since fire ants probably reduce that, I would consider them detrimental.
There are fire ants that made it here before - there are species native to the southern US that do comparatively little damage, because they are integrated into the local ecological communities.
These introduced species have failed to make it here over possibly millions of years, even though Pleistocene climate change could potentially have allowed migration through open-country corridors through areas that are (or were until recently) rain forest, where these species do not live. It’s extremely unlikely that these particular species would have reached the US without human help in anything short of geological time.