Ah so it's that the playbooks are imperative and "dumb" (does exactly what you tell it, rather than inferring "these actions must happen, do them in a sensible order"). That makes sense.
Dove into the puppet docs/wiki article, I guess part of the difference as well is that puppet considers each "unit" a resource, vs. ansible being a "module/action".
It does seem like ansible roles have a dependency mechanism, I guess that might be the intended level for a "declarative" approach in ansible, to encapsulate the playbooks/modules underneath that are more of an implementation detail at that point.
Puppet is declarative, you simply say "these things must, or must not, hold" and a combination of user-declared and inferred dependencies arrange the sequencing, which can be different in each run (as long as the before/after dependencies hold).