IMO, a commit without a TODO is very very close to a commit with an untracked TODO. If somebody decides that the issue isn't worth filing a ticket then okay. If somebody isn't willing to file a ticket then it isn't like they were likely to write a detailed comment explaining all of the relevant context. "TODO - clean this up" is pure noise.

A loose TODO lying around the codebase almost certainly won't actually get acted on and there is no opportunity to discuss or prioritize it.