When NOT to use the API

The API is primarily intended for editing. For read-only purposes or projects, see OSM API policies.

For bulk upload scripts or data modification, the direct API use may not be the proper mechanism

The modern version of creating a bulk upload or modification script is to build a changeset, load it into an editor like JOSM, and verify the work prior to commit.

You can also use the API to upload a changeset in an atomic manner.