Slack apps can be complex due to the need to coordinate messaging content, channel, user interactivity, and integration with your product's backend, which includes managing user permissions and data security. Knock simplifies this process by treating Slack as just another notification channel and providing abstractions that help model Slack concepts differently from other messaging platforms. Using Knock, Slack is modeled as a channel and messages are treated as templates, allowing for easy management and integration through its SlackKit integration. The tutorial demonstrates creating a simple Slack integration using webhooks, explaining the use of objects to represent non-user Slack channels and users to store specific channel data. This setup enables seamless notification workflows, whether sending messages to Slack channels or individual users, while maintaining a central repository for message templates and accommodating dynamic content through liquid markup language. Knock aims to ease the complexity of working with Slack's API and platform, providing tools to manage Slack alongside other notification channels efficiently.