While the concerns with cancer aren’t as great as with females (85% by age three in females) sex hormones ARE carcinogens and they shorten life expectancy so theres a pro.
Neutering also decreases territorial marking and aggresive behavior.
You have the option of getting a second bunny at some point.
Neutering decreases sexual frustration which makes his psychological life better (not nice to have the horomones and no bunny to play with)
Neutering is also far less invasive and risky then spaying

Hope I convinced you!!

I have a spayed female and now a neutered male.  Jessica was spayed when I introduced Leo into our home.  I had toggled back & forth about getting Leo neutered.  He was never a hormone wild, marking male.  He had his spells of getting horney w/ Jessica but it was VERY seldom.  We made about 4 attempts for a neuter.  1st time:  turned out he had teeth probs I had to pay for first.  2nd time:  one of the cats soaked up my vet money.  3rd time:  He had his teeth filed/ trimmed at the same time.  He had some major bleeding w/ his teeth and they were very concerned about keeping him under anesthesia for any longer.  4th time:  It happened he got neutered!

The Long & Short:  I didn’t really see the behavioral point of getting him neutered.  I didn’t have to worry about babies b/c Jess was fixed.  However, I would really regret any type of reproductive cancer to happen to him!  My ex was a vet nurse and it always broke our hearts when an animal developed reproductive cancers b/c they could have been completely prevented if they had been spayed or neutered.  Also, male rabbits are still prone to mammary tumors!  This is not only a female rabbit issue.  It’s my understanding that it s a rabbit issue.  I think it’s worth spending the money for prevention and longevity!