Insurrection is almost $20, and Champion's Helm is over $30
Premium pump spells like Scale Up and Mutagenic Growth make it trivial to generate lethal damage with the card, essentially putting it in a similar category to Infect creatures
It is rather on the all in side, not only because it hits your total resources pretty hard but because of the style of deck where Smallpox is optimal - if all your cards are cheap (or at least the ones you plan to cast) then you are less likely to have that much late game legs
After all, there were only twelve hybrid cards in the file
15 Magic: The Gathering cards 4 Traditional foil commons or dual land cards From among 81 commons and 10 common dual lands 3 Traditional foil uncommons 1 Traditional foil full-art driver's seat land 1 Non-foil revved up common (46.9%) or uncommon (53.1%) 1 Traditional foil revved up common (46.9%) or uncommon (53.1%) 1 Traditional foil default frame rare (85.7%) or mythic rare (14.3%) 1 Aetherdrift Commander (DRC) card This can be a non-foil extended-art rare (84.25%), non-foil borderless mythic rare (10.5%), or traditional foil borderless mythic rare (5.25%)
I think its a nearly perfect card