What problem does this address?

Themes have the ability to define element color styles for the core/post-content block (container), however there are no user level interfaces for modifying those styles. For example, a theme could have something like this in its theme.json:

"core/post-content": {
				"elements": {
					"link": {
						"color": {
							"text": "var(--wp--preset--color--secondary)"
						}
					}
				}
			},

However there is no color panel for modifying the block level styling for this block:

What is your proposed solution?

Enable color supports for the core/post-content block.