[EM] Advantage of MDDA over Approval?

[Jan Kok]

I'm having a hard time wrapping my head around MDDA, partly because
I'm not sure about the definition.  A candidate A must be ranked lower
than some _specific_ candidate B on a majority of ballots in order to
disqualify A ("ranked lower" would include A not appearing on a ballot
while B appears on the ballot), is that right?

So, what is the advantage of MDDA over Approval?  If some candidate
has majority first-choice support, then that candidate will win in
almost any system.  If no candidate has majority first-choice support,
then MDDA is just Approval.  If more than one candidate gets more than
50% approval votes, I would think it would usually be because of
second-choice votes for a compromise candidate, and the compromise
candidate would likely win, same as Approval.

I think the main technical problem with Approval is that it can be
difficult to decide whether to vote for compromise candidates in
addition to ones favorite.  Does MDDA help?

Thanks,
- Jan