Why are patterns useful?
Useful applications almost never exist in isolation. They are almost always integrated in a wider ecosystem, which is especially true for microservices. In other words, the integration specification and requirements need to be communicated and understood by other developers and architects.
When using patterns, you have a common language that is spoken among the technical crowds, allowing you to be understood. It's really about better collaborating, working with other people, exchanging ideas, and working out how to solve problems.
The main aim of patterns is to save you time and effort when implementing new services, as you have a standard terminology and blueprint to build something. In some cases, they help you avoid pitfalls as you can learn from others' experience and also apply the best practices, software, design patterns, and principles.