If you can cast a spell with delve from your graveyard using flashback like the ability from Snapcaster Mage, you can apply all the rules from the mechanic
However, you do have access to some of the best artifact removal in the game which, when paired with Liquimetal Torque, can also become much more flexible
It depends on how hostile the format is for it
You don't normally want to have to think about getting to 6, five is hard enough
The combination of Courser of Kruphix and Underworld Connections on the field means we can also go through our deck quite quickly while being able to see what were going to draw
Unlike other cards with this effect like Renata, Called to the Hunt and Good-Fortune Unicorn, you can add counters to Arwen so your board scales in kind