Confused about timeout for manual-approval 72 hours or 6 hours?

[thardy]

I posted this on StackOverflow and haven't seen any knowledgeable responses...

The documentation mentions...

"Note: This approval duration is subject to the broader 72 hours timeout for a workflow. So keep that in mind when figuring out how quickly an approver must respond."

Then a little further down it states...

"A job (including a paused job) will be failed after 6 hours"

I find the above two statements to be incredibly confusing. How long would someone have to approve, 72 hours or 6 hours? How can someone have 72 hours to approve if the job is automatically failed after 6 hours? What is the difference between the two timeouts? Can I get a little more detail on what scenarios define each?

I'm hesitant to even try this action because it sounds like it will just constantly burn through usage limits.