Being able to nuke any artifact or enchantment whenever a creature you control enters is a massive gain, especially if you're playing any number of notable commanders who enjoy tons of tokens entering the battlefield, like Jetmir, Nexus of Revels (one of the best Cat cards for Commander)
Reanimate it, activate once, and youre already ahead
In particular, playing cards with Resist works well, preventing the Sheriff dealing its damage
If the copied creature is itself a token, the tokens created by Aggressive Biomancy copy the original characteristics of that token as stated by the effect that created it, with the listed exception
Even if you are ahead in ever metric, a 4/5 is a perfectly acceptable body to widen your lead
An Example Deck: Ephara Lets look at one of my decks