Illusions play just like regular cards but have a new effect called Vanish that banishes them if they are targeted by any action The illusions on display in the Starter Decks seem like they are tuned just a bit stronger than regular cards of the same cost with the Vanish drawback acting to balance them out
The comfort it gives in construction knowing you are able to go longer and the threat of it when it is in the bin both contribute a lot to the value of the eternalize
TCGplayer comes out almost identical at about $6.50 per pack, while Walmart lands closer to $6.96 per pack
To keep things simple, Emry hasnt gotten better because of this rule change, per se, but rather Affinity as a whole is now slightly better positioned as a whole
It depends on what kind of decks are available to slot it into, but Id be shocked if it was anything less than just good
Mark Rosewater addressed this issue in his UNSTABLE FAQAWASLFAQPAFTIDAWABIAJTBT: Half-Squirrel, Half-Pony allows you to replay any creature with an enter the battlefield effect (which includes all host creatures) as many times as you want