A common complaint from advanced Elements Organizer users is that you can't open jpegs or tiffs directly in ACR, whereas that is possible in the editor.
There has been an add-on by John R Ellis : OpenInAcr to compensate for that in older Elements versions.
As explained in the other post, the ability to open jpegs in ACR is very important for Organizer users. One wonders if the lack of this feature is not deliberate to avoid competition with Lightroom...
On the other hand, a solution from the DNGconverter would be even better in my workflow.
There, I do not think it's a deliberate choice, it's probably because the ACR developpers don't see the point. Many Elements users already use the DNGconverter for its main purpose (new cameras, avoiding to upgrade PSE every year...), they would easily use it also for jpegs.