JIRA has a concept of the "universal access key" to submit a form; by default, this key is Alt + S. While Confluence does not have this idea, it would be really nice to have this to be possible for common functions like create, edit and commenting on a Confluence page.

I believe this is already true for Update (Save) but not for Comment (current it's Post). Maybe the term Post can be rephrased as "Submit" so we can use Alt + S there as well?