If you've decided you don't want any (more) kids in the future, a vasectomy is the easiest way to insure that with the least likely side effects for anyone.
Why would you force your wife to be subjected to the side effects of birth control if you can get a simple out-patient procedure?
Because you don’t want to give yourself the chance to change your mind.
It’s worth nothing that hormonal birth control doesn’t really agree with all women. Hormones have health complications, including mental health. I would never push a partner towards taking them.
Well yeah if you don't know yourself well enough to know that you never want kids in the future, you obviously wouldn't get an irreversible procedure.
But everyone has a point after which they decide they don't want more kids and it's insane to force your partner to continue being responsible for that with all the downsides when you can just get a snip.
And if you're thinking you're gonna want kids 20 years from now as a man in his 30s or 40s or later, run that by your partner and see what she thinks about that.
Because why would you do something essentially irreversible when the other party has a temporary solution. I’ve changed my mind about things plenty of times, why would I do something I regret 20 years from now.