With cats as with dogs, it's all about responsible owners.
My cats have always had outside access during the day. It is supervised, as I do not have a cat flap, and they are always inside between 5pm and 10am. That "in time" is earlier in the winter when it gets dark earlier. My current cat only goes out when she sees the sun, and sits on the drive guarding my car. She comes in to use the tray. During the winter, she prefers to roast herself in front of the radiator.
She was a prolific hunter when younger, but now that she's twelve, I might get one mouse a month if I'm lucky!
As for wildlife loss, pointing the finger at cats is unfair, considering how much impact we as humans have on the environment. The real biggies are climate change, loss of habitat and the use of weedkillers, pesticides and poisons. Especially in rural areas. It's a many faceted issue to which pointing the finger at one single factor - in this case, cats - is kind of, well, pointless.
As for the benefit of cats. It's just the bond and trust that is so rewarding. And there's nothing better than cuddling a purry cat when you're not feeling 100%. Cats are definitely a lot less work than a dog and are much cheaper to run - though some breeds (persian & sphynx in particular) need daily grooming / care to prevent issues. Cats are wonderful individuals with a wide spectrum of personalities, though the girls definitely have more brains than boys.
Comparing dogs to cats is like comparing apples and pears. They are different, though equally rewarding. But cats have the advantage if you do not have the time to go and exercise a dog. A lot is dependent on your lifestyle.