After approving a publishing workflow message in pulse, there is not viewable marker that this workflow has been approved (or rejected) in any kind. The only option is to open the message again and try to approve it.
Also other participants of the same workflow (for example when a group is informed) won't be able to see that it was already approved by somebody else.
If you think in a real live system with many publishing a day, this is very hard to keep track of what is approved and what not. Especially if a whole team of approvers have to collaborate.