The two creatures arent on the battlefield at the same time
If that creature dies this way, its controller creates two tokens that are copies of that creature, except their base power is half that creature's power and their base toughness is half that creature's toughness
These include creatures such as Agent Frank Horrigan (indestructible, proliferate), Alpha Deathclaw (destroys permanents), Consuming Aberration (mill), Ezuri (proliferate, card draw), Fathom Mage (evolve, card draw), Lily Bowen (+1/+1 counters, life gain), Marcus (card draw, +1/+1 counters), and many more
Drop Valley Rotcaller with a haste enabler like Swiftfoot Boots and an army of squirrels, and youre set
What I ended up with didnt have very many enters-the-battlefield triggers, but thats because there arent many Rogues that have them
Milling became so popular that it's now common to see entire decks built around the keyword