These are used either with specific effects that can interact with artifacts, or used to ramp into high-mana spells
This card's usefulness comes in the form of its second ability that allows Tetsuo to be tapped for four mana, destroying any target tapped or blocking creature, functioning as repeatable removal.While, Tetsuo Umezawa can keep opponents on their toes through its removal, its price is largely from a lack of availability rather than due to its strength as a card 9 Dong Zhou, The Tyrant: $159.99 Dong Zhou, the Tyrant's price tag of $159.99 is not due in part to its quality, rather its incredibly limited print run
They did this through the creation of the DCI and the banned and restricted list, but they also did this with Revised
This is unlikely to happen with Born of the Gods, though its possible
Cruel Ultimatum
These will certainly be draft-around bombs in limited, and I can see them having a big impact on Commander as well