While this doesn't affect value, it adds personality to the card and can help with identifying which specific printing of a card you have, as different printings sometimes use different Pokedex entries
they are sourced from compromised devices and are frequently used for fraud, meaning their IPs are on every retailer's blocklist before you even try them
Since ex cards are considered Basic Pokemon, being able to put it and all attachments back into your hand can mean the difference between winning and losing
Other times, youll hold it back because itll probably die in combat, in which case Phenax allows you to tap it to mill seven
Eight mana for, at minimum, three 5/5 lifelinking fliers swinging in and three permanents from your graveyard, is an absurd rate
For casual play, bears are decent enough that you can just do that