Is is better to avoid using internal page statuses?

[DrQuincy]

When looking at the source there are quite a few page statuses beyond those visible in the Status > Settings panel; these are marked as #pw-internal in the comments. Is it better to avoid using these as it could mess up how PW works? I just wondered as the 'flagged' status could potentially be quite useful. I can just unpublish though and if it's possible uses these statuses could cause issues I'll leave them alone.