The fact that split cards change whether its in your hand, graveyard, or on the stack is important because of how rules consider each spell
That said, they have some drawbacks you should be aware of: Some weak cards : This is, in part, a side effect of the fact that precons are designed to starting points which players build on: there are some weak cards which are meant to be identified as underperformers and subsequently upgraded
Triome Lands These lands are pushed very hard, and every midrange deck will want to play a number of them
Broadly I would look to play things like Ravenous Chupacabra over this as they are just more reliable but the ceiling on Assassin is far higher
Elspeth, Storm Slayers Halo Foil variant is going for a whopping $400 right now, but thats actually slightly below market value
The date range above is very compelling for two reasons