A good rooster does a lot of things that help to protect their flock that often go unnoticed.
As others have correctly ime, mentioned; cockerels are pretty all round hopeless. That's youth in any species. If they don't die and grow up in a mixed age flock with a senior rooster, but often more important, a senior hen then the survivors will learn. It seems to me the poor cockerels aren't in with a chance with some people and are expected to know what to do and when to do it because they are males.
What about your hens? Maybe they feel safer having him around. Maybe the hens like how he stops the usual hen bickering, maybe while they're busy stuffing their faces while he stands guard they feel more secure. Maybe when they go to look for nest sites they like to have a cockerel, or rooster accompany them. Maybe they like the mating knowing that if that big predator on two feet doesn't steal their eggs they might be able to hatch some chicks.
Maybe people who want to keep chickens should learn a bit about what motivates a rooster and what he actually does for his hens.
Of course, if you just want to keep a few hens and not really keep chickens at all, then by all means don't have a rooster.
@Shadrach, I loved your responses in this thread. Until not so long ago, I was guilty of just expecting my cockerels to assume their manly duties faultlessly and immediately, and I was upset when they didn't. My first cockerel died at 20 weeks, defending a hen from a fox. My second cockerel was a rescue dumped at the neighbors and was introduced to the flock around 5-6 months? Hard to say, but he was scared of EVERYTHING from weeks of being feral on the neighbors farm, unwelcome by any of his birds and chased by his dogs. So he was a terrible protector for a long time, and then I sadly had to give him away as he was too affectionate with my (too few) ladies. Eventually, though, he did assume his roosterly duties and he was drop dead gorgeous to look at.
My current cockerel I've had since 6 weeks and is now about 9 months and was put in with my older hens around 24 weeks. I see a big difference in how he's matured and how they all relate to each other, being different ages. I got similar-age pullets at the same time as him and obviously he mates them more, but the older birds have certainly taught him some manners. In the beginning, he was pretty ruthless and would mow them down to mate them, then stay on them for a while. Now he is a gentle and delicate flower that occasionally hops on them and quickly off again.
I really expected a lot of my previous roos because I didn't really understand chicken dynamics. But I love having a rooster for all the reasons you mentioned. I see obvious affection between my current roo and his best girl, Sally. He is kind to me and tidbits the girls nonstop, which is sweet to watch and I think the girls like being brought food. He keeps them together as a flock when they're out, which isn't much these days because of red tailed hawks nearby -- which he fought off of my little Ameraucana hen, suffering only a few scrapes and lost feathers. After the attack I watched him very carefully move the girls to the run, letting them all go in before him, and then into the coop for bed. Of course I try not to project emotions on them, but even without emotion it is obvious to see that he is a good rooster in most all capacities, and the older hens, while one still remains more dominant, have taught him manners *and* seem to mostly respect him. He also remains vigilant against predators in the run, and always alerts when the hawks come to sit in the trees and watch them. He is as valuable to me as the hens.
But previously, I definitely just expected them to hit 30 weeks and be professional roosters. With Ollivander (my current one), I have found a lot more compassion and understanding, and also expect he will really hit his stride with everyone this summer when he's a little over a year.
I really appreciate all the comments here because I really didn't want a rooster at the beginning of my chickeneering but have come to love them and appreciate them a lot.
That said, there are certainly bad roosters, of which I've known some, and their purpose seems to be as food rather than company.