What is server base url purpose in OAuth credentials

[Victor Khazanov]

I'm developing integration (deployments REST API) from our app to Jira Cloud 

When I create OAuth credentials (https://support.atlassian.com/jira-cloud-administration/docs/integrate-with-self-hosted-tools-using-oauth/) I need to specify Server Base URL

However, it doesn't matter what I write there , my credentials (cliendId and secretKey) are still  valid.

I see this field is required