When not to use an API

In an earlier post, I covered how there are now "APIs with everything"

However, it is not always that a system designer would use an API for integration. Here are some scenarios where you would consider NOT using an API:

• When an API is not available, for example the vendor has not developed one yet
• When an API does not meet the necessary non-functional requirements (for example: security, performance, volume, availability, etc.)
• When you already have a tightly coupled integration between two systems and there is no need to change/upgrade this 

Have I missed any?