docs: add popular use cases section to README (#12297)

* docs: add popular use cases section to README

   This commit adds a new section to the README that outlines common
   use cases for Kyverno, helping new users quickly understand its
   practical applications. The section is organized into four key
   categories: Security & Compliance, Operational Excellence, Cost
   Optimization, and Developer Guardrails.

Signed-off-by: Karthik babu Manam <karthikmanam@gmail.com>

* docs: add popular use cases section to README

This commit adds a new section to the README that outlines common
use cases for Kyverno, helping new users quickly understand its
practical applications. The section is organized into four key
categories: Security & Compliance, Operational Excellence, Cost
Optimization, and Developer Guardrails.

Signed-off-by: Karthik babu Manam <karthikmanam@gmail.com>

---------

Signed-off-by: Karthik babu Manam <karthikmanam@gmail.com>

README.md

@@ -1,4 +1,20 @@
-# Kyverno [![Tweet](https://img.shields.io/twitter/url/http/shields.io.svg?style=social)](https://twitter.com/intent/tweet?text=Cloud%20Native%20Policy%20Management.%20No%20new%20language%20required%21&url=https://github.com/kyverno/kyverno/&hashtags=kubernetes,devops)
+<!--
+Copyright 2024 The Kyverno Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
+# Kyverno [![Tweet](https://img.shields.io/twitter/url/http/shields.io.svg?style=social)](https://twitter.com/intent/tweet?text=Cloud%20Native%20Policy%20Management.%20No%20new%20language%20required%1&url=https://github.com/kyverno/kyverno/&hashtags=kubernetes,devops)
 
 **Cloud Native Policy Management 🎉**
 
@@ -38,6 +54,36 @@ Kyverno installation and reference documents are available at [kyverno.io](https
 
 👉 **[Sample Policies](https://kyverno.io/policies/)**
 
+## 🎯 Popular Use Cases
+
+Kyverno helps platform teams enforce best practices and security policies. Here are some common use cases:
+
+1. **Security & Compliance**
+   - Enforce pod security standards
+   - Require specific security contexts
+   - Validate image sources and signatures
+   - Ensure resource limits and requests
+
+2. **Operational Excellence**
+   - Automatically add labels and annotations
+   - Enforce naming conventions
+   - Generate default network policies
+   - Validate resource configurations
+
+3. **Cost Optimization**
+   - Enforce resource quotas
+   - Require cost allocation labels
+   - Clean up unused resources
+   - Validate instance types
+
+4. **Developer Guardrails**
+   - Enforce ingress/egress rules
+   - Require liveness/readiness probes
+   - Validate container images
+   - Auto-mount configuration
+
+Each use case includes ready-to-use policies in our [policy library](https://kyverno.io/policies/).
+
 ## 🙋‍♂️ Getting Help
 
 We are here to help!