* other posts have mentioned that while "rejecting" a task will change the status, "approving" a task doesn't change the status in any way, which makes multi stage task approvals messy (confusing and unsatisfying)
* users have, on the whole, wanted one report to look at. Having approvals messes this up because now they have to look in two places for their work.
* for whatever reason, users have no problem ignoring a pending approval and continuing on with the workflow. We also regularly get help requests from folks wondering why they're unable to close a project even though it's 100% complete, and half the time it traces back to an unapproved task (the other half traces back to an open issue)
We do have one workflow that has gone in a different direction and use a custom field for all of these steps. So to them, this would be one task, status would be set to In Progress, and then their team custom field would have options for Data Pulled, Data Reviewed, Copy Created, and so on. It's not for everyone, and particularly not if all steps have to be documented as part of the historical record.