It's possible to make high-quality tintypes, but it's not easy to do it reliably. At my business, Photobooth, we've made over 4000 pretty good ones in the past three years, but it's still a struggle to get good results day in and day out. Here's a few:
We've taken tintypes on-site at many events at it is a royal pain to get good consistent results, let me tell you. It can be done, but it's not easy. When you tell someone at an event: "Okay, that pose is perfect. Please stand still while I put the plate in." What usually happens is they look at their phone or wave at a friend, which puts them out of the narrow plane of focus. Bam, a plate is ruined and it's five minutes at least until another is ready.
Victoria Will and Josh Wool are pro photographers but they are not experienced tintypers, so I'm not surprised that the tintype quality is technically not very good. But Victoria clearly has a connection to the subjects, and the pictures have proved to be effective. Many people like them and are talking about them, so they are successful. One could even argue that the Photobooth style of clear, well-lit tintypes would not have been as effective.