Ants are Gods creatures and serve a purpose in the cycle of life. It has been proven they can help with pollination and have the ability to move the earth around helping with that cycle. They eat/kill other bugs that can damage your crops and probably help in other life cycle processes.
With that said, I kill any and all that I see! Being in a temperate zone (9A), ants thrive here. Several species have infiltrated/ migrated into the south and will probably be headed your way as they evolve.
My nemesis is the Fire Ant. Which, I've read was imported from South America back 60 or so years ago in a shipment of bananas (so "they" say). Can't put nothin on the ground without them building a nest underneath it. And they are vicious little farkers. Defending their nests with a vengance! Their stings will turn into a pustule which may reach 1/4 " across and if you don't take care of it quickly it will get infected.
During heavy rain event they will elevate their nest. Into a lot of places we do not want them. I have had them come into my house, through the pipe and electrical entrances. And build nests inside the walls. They have gotten into the contact box for the water well, disablin it until I could clean it out.`
When I first came here to SE Tx, almost 50 yrs ago, they were here but not in great numbers and did not range much further north. Now they are found as far north as the Dallas area, couple hundred miles north of us. Comin soon to a neighberhood near you!
And there are the plastic eating ants, I forget their name but they will infiltrate a vehicle, or house and they love to eat plastics, Especially the soy based plastics the environmentalists fawn over now and a lot of electrical insulation is made from!
The non- native ants have displaced the God given native ants that were not nearly as destructive and served a real purpose in OUR environment. I have posted several times about the fire ants in my compost bins and I'm sure some are gettin tired of listening to it. But in My environment they are a real threat.
If nothing else, think about seeing your child or grandchild come screaming to you with hundreds of ant bites like I have described above on his/her legs.
Sorry for the rant but I hate ants!