The total number of MTG cards depends on what Magic: The Gathering card count you want to use there are around 27,000 unique cards, but many more if you start to include reprints, variants, and out of game cards like art cards and tokens
The Assembler automatically puts a +1/+1 counter on the Walker since it would just die immediately, given its 0/0 stats
If you are an experienced deck builder, why not offer them your knowledge
Simply passing the turn with four white mana open creates hesitation across the table
I should clarify that Im not actually advocating for a ban here, Im just trying to illustrate how format-warpingly powerful this Pirate is
In a sorcery/instant matters build it's a great way to rack up those triggers