Mason wants us to evolve our Goldeen into Seaking (recall we had the Seaking card in our initial hand) and then attach a psychic energy card to Seaking, which, when combined with the water energy card we attached to Goldeen in turn one, allows Seaking to use its Waterfall attack
If you somehow visit Swinging Ship after the first combat phase of a turn has ended, it won't have any effect
Playability drives demand
That comes at the cost of one life per draw, but Phyrexian Arena's a black Commander staple that people have been fond of for quite some time, so it's nothing new
This set added more myriad creatures and introduced cards that spread the ability to other permanents
Naya decks have cards like Mana Echoes and Dockside Extortionist which help you generate more than three mana every time you blink the creature making it profitable to loop the creature