How often are you stalling with siren/rejuv/adrenaline on your own creatures? Guess it's also useful to sing to your own creatures for doublecast
Yeah, that is a nice play if opponent's creatures deal less than 8 damage, but with life nymph, may get more mileage from adrena+siren opponent. Siren proc on adrena-rejuv-own creature is 8-heal then 20-heal on attack, assuming 3 attack creature.
I noticed during Fortune Teller that Siren, and, especially Surgeon, is underrated. They both provide nice ecosystem services.