No actual packet is used with a spell strike; touchcasting requires an actual packet; therefore touchcasting a Spell Strike is not allowed. The intent of the "as if it were a spell packet" wording is to clarify that touching someone's possessions (garb, shield, etc.) still affects them.
It's also strongly implied by the wording on the scroll, which states that it explicitly cannot be accepted through protectives.
-Bryan Gregory
ARC