We have very complex business logic directly tied to our Rails / ActiveRecord validations (and, btw, they are a blessing).

Also, it's not only validations. We rely heavily on ActiveRecord callbacks, which are awsome. We have hundreds of before_save, after_save, after_create_commit, and so on, all over our models, and they are also indispensable to our business rules.

For a simple example, if I need to sync my User model with Mailchimp after an e-mail update, this tool would not fire the after_commit callbacks.

Having said that, I would definitely pay for a "service" that would act as gem in my application, mount itself on a specific endpoint (think /turbo-admin), and give me the exact same feature set I saw on this landing page, but with the ease of mind that all our updates would go through Rails, running validations and callbacks.