If people arent looking to buy the cards you have, it could take months to get rid of them, if at all
If you use one of these cards on a cheap creature, its too small for the effect to matter, and if you use one on an expensive creature, why does that creature need a conditionally relevant keyword
Im sure people will find a way to copy or cheat this out way cheaper than I already listed, exile their entire library, and then drop a Thassas Oracle on the field
Pantlaza's Discover ability means that each dinosaur you cast has the potential to trigger a cascade, letting you fetch up one or potentially more other random dinosaurs from your deck (worst case scenario you hit a mana rock or something)
Its a fine rate for the effect, but the addition of flashback makes this almost the reanimation equivalent to cards like Timeless Witness you can reanimate two things, or gain value from discarding or milling it