Well if you're going to try that argument, I want a note on Rustler telling me not to SoR it. Just sayin'.
Which is a completely straw man argument.
SoR + Rustler is a unique interaction purposely designed to avoid the exploit of infinite quanta generation. How does Momentum applying to spell damage cause anywhere near the same type of exploit to the game?
Furthermore SoR + Rustler yields an effect which you would never expect to occur just from reading the two cards separately. Momentum however makes no indication that its ability is solely reserved for physical damage or spell damage. Therefore I make the argument that Momentum should apply to both physical and spell damage, which requires no new note to be made on the card itself. This note would however be warranted, based on your argument, if Momentum only applied to physical damage. So in other words, your comment does nothing except to reinforce my argument.
That aside, I have another strange phenomenon I thought was worth mentioning. Consider the following:
1. Antimatter'd creatures do not receive additional damage reduction from shields.
2. Antimatter'd creatures are not affected by the reflective status.
3. Holy Light is not affected by the reflective status.
4. Antimatter + SoW will cause a creature's attack to be affected by the reflective status, effectively healing their owners.
I list these facts to address the possible logical explanations for Antimatter'd attacks being affected by reflective shields. It has been agreed upon that Holy Light is not reflected because it is healing the player instead of dealing damage to them. Therefore the logical explanation for Antimatter'd SoW'd attacks being reflected would be that it is dealing negative damage (which is somehow different from healing the player I guess). However, Antimatter alone does not receive damage reduction from shields meaning that the attack is no longer physical. If the attack is no longer physical then it would be natural to assume that the creature is now dealing spell damage or is healing the opponent, thus bypassing damage reduction. But then Antimatter alone is not reflected, which would cause my method of logic to conclude that Antimatter converts the attack to healing. Therefore Antimatter + SoW would seem to be parallel to Holy Light such that it is not affected by the reflective status.
Is this not the case because SoW converts the "healing damage" into "negative spell damage"? Really, the more I try to grasp the concept of physical versus spell damage, the more I seem to confuse myself :
D