Most people will just assume that it is entirely a kinky thing, and while it can be, it’s not the whole answer.
In reality, there a many reasons why a man would enjoy this.
Some simply want to show their uttermost devotion to their wives. Others want to use it as a way to increase their desire.
A few even use it as a way to level the sex drive: if a man desires sex every night, but his wife only a few times per week (or per month), chastity might simply be a way to restore a balance as the wife can wear the key when she is interested, and store it in a drawer when not.
But I want to offer two other arguments which are not at all sexuality based, but which often come when talking about the benefits of chastity
Selflessness
Now, this is often mentioned: men in chastity become more docile, more helpful around the house, but this avoids the main reason.
Men in chastity do not become more keen to do chores out of a way to convince their wives to unlock then, but rather because they learn to think with their head, not their dick,
Ok, that’s reductive. Let’s explain it another way.
Man usually have sex on their mind and focus only on their own benefits. It’s not that they are rude or selfish, but that’s the hormonal pressure: men compete, women cooperate.
With chastity, men have a different focus. They see things differently. They are made aware of, for example, how little they contribute to the chores.
It’s not that chastity made them little obedient mindless slaves to their wives, it’s that by not constantly thinking about sex, they notice what has to be done more. They focus more on her, rather than on them.
By (sometimes) taking their orgasms out of the equation, they learn to be selfless. To see the needs of others.
Can it be taught in other ways? Sure, but that behavior starts in the school yard. It’s not easy to unlearn.
Mindfulness
Men are also single-minded: if they are working on a project, it’s all they think about.
Most men, at work, forget about their wives! Sure, they often put a framed picture on their desk, but most barely look at them.
When they are concentrated on a task, they focus on it and forget the rest of the world exists.
Several men who work in an office will sometimes do overtime not because they needed to work late, but because they were so concentrated that they missed their time to leave!
In fact, a lot of men who flirt with waitresses on their lunch break often haven’t thought about their wives since they left for work, and in some case when they woke up early, since they went to bed the previous night.
Male chastity helps to refocus the man’s life on his relationship.
It doesn’t prevent him from losing focus at work, but makes him remember his marriage, his wife, his commitment to her.
Every time he shifts a little on his chair, he remembers why he is even at work: to provide for his family.
That he doesn’t live to work, he works to have a life. At home. With his wife.