Yes, you might think that K-cups and coffee pods are interchangeable as both of them look similar. But in reality, they are different, like day and night. Although both are a single serving of coffee ground, pods are generally packed into filter paper and wrapped in foil for keeping it fresh for a longer time.
On the other hand, K-cups use tiny plastic cups to store your serving of coffee. Coffee pods can't be generally used with as many devices as K-pods are. You can not use coffee pods in Keurig machines. Also, there are fewer choices for coffee pods as compared to K-cups. But when it comes to sustainability, then coffee pods are a clear winner thanks to their typically environmentally-friendly packaging.