source tracking -- why not use metadata list results? (instead of sourcemember)

[jon-freed]

Hi - Is there a reason why we should not be using metadata list results to determine when metadata was last updated versus using the source tracking functionality in the source-tracking library?

One advantage of using metadata list results is that, unlike the source tracking functionality, it is available in production org instances.

[mshanemc]

• it's also a bit incomplete (ex: missing namespaces, not being able to list StandardValueSet)
• it's one-query-per-type so it's quite expensive (in terms of api calls) to scan an org for changes