Huh, Round 2 prize is AMA. Guess that means everyone has AMA now xD
And the EX Trader also has AMA. Meaning you can get 2 AMA from this event alone, and if you got at least 1 copy from Arkana during the Marik event, you'll have 3 copies.
None, it's just that some people (not me) like to have 3 copies of everything for whatever reason, even if the card is always used at only 1 or 2 copies.
Why not have 3 of it? Unless its going be from tickets or box, it's nice have 3 since we never know when 3 will be necessary and its the maximum set, so it's good have all.