Are ansible_user in inventory vs remote_user in playbook equivalent?

I am trying to run an Anisble playbook against a server on an account other than the one I am logged on the control machine. I tried to specify an ansible_user in the inventory file according to the documentation on Inventory, however it does not work the way I expected.

On the other hand adding a remote_user argument to the playbook worked for me.

Are the ansible_user in inventory file and remote_user in playbook for different purposed? What is the ansible_user used for? Or why doesn’t Ansible observe the setting in the inventory?

they are the same, but ansible_user is only a 2.0 thing, in older
versions its ansible_ssh_user