I believe the logic is that dry food is better for their dental health, because the firm texture is better at scraping away plaque, although there's definitely disagreement on that, and there are other ways to address dental health.
The argument for wet food is that it does a much better job at keeping them hydrated, which is important for a number of bodily functions, including urinary health. Studies say that while cats fed primarily dry food likely drink more water, their total fluid intake is still lower and they're often still chronically dehydrated (which is also not good for dental health). Moistening kibble can help, but it's still not as effective as wet food for ensuring your cats are well hydrated.
My oldest strongly prefers kibble, but after his urine test at his 1 year check up indicated early signs of urinary troubles, the vet said to either switch him to 100% wet or to a prescription kibble. It took some trial and error, but he's on 100% wet now, and only gets crunchies as treats. His urine tests have been great, and the vet also said his teeth look good.