When working in conjunction with spells such as Fury Charm and Timecrafting that are capable of removing time counters, one would be hard-pressed to find more efficient means of playing massive creatures within the Izzet color identity
Its standard variant is much more reasonable, at around $11
1 Restore
Its important to note that many other factors can affect a cards rarity and value, including misprints, signatures, condition, PSA grade, and market availability
While it is possible according to the MTG rules for a Wall to be created without defender, as of the time of writing (August, 2021) none have been published
It'll usually buy you a turn from attacks and interaction, but discarding a card and skipping your draw step each turn is a steep cost to keep it around