I think its the neighbours' opinion that counts, for many of us, Deansmig, and our other halves who like to sleep in past 4 a.m. of a summer morning, Cockerels are noisy of course and don't have an off switch. Keen as I am on keeping poultry, I would be disturbed if a neighbour got a cockerel, we had that a few years ago and it was a real pain to the whole street.
I think they are decorative, add to the life and interest of the flock dynamics, and they do look after the hens in a natural way. Fine if you have plenty of space and don't keep them near enough to people to disturb them, but they are an extra mouth to feed, unproductive if you don't intend to breed from them, can be aggressive to humans, can wear away the feathers on their hens backs, and will take up space in the run that could be occupied by another egglaying hen. There's the temptation for indiscriminate backyard breeding from cockerels that have been rehomed ir various reasons, and then used with whatever hens happen to be in the flock, which can result in poor quality stock that nobody will want, especially the next generation of cockerels that have to be dealt with in some way - the problem can escalate!