(2025-06-06) A spell cast using flashback will always be exiled afterward, whether it resolves, is countered, or leaves the stack in some other way
When someone hits your giant multiply-mutated Kaiju with a Rapid Hybridization and you get a 3/3 Frog Lizard token, you can now find ways to put keyword counters on it
Its designed to allow you to keep myriad tokens, but the rules text works with so much more
I imagine a common use case for this would be after a sweeper, so you wouldn't have a ton of creatures in play to help you cast it, but it's just nice having more ways to get this onto the stack
Second of all, its among the cheapest cards that have this ability, which gives you a lot more +1/+1 counters in the third, fourth, and fifth turns, when you would be waiting for other bodies to come online
That activated ability can be absolutely criminal, whether you use it to finish someone off or just to bring them down a peg