From a competitive standpoint, not many of these see much play, although Ketramose, the New Dawn is the face of a hot new Modern combo deck
Secondly, while declaring blockers, if one creature in a band becomes blocked, the whole band does as well (702.21h)
With pokemon card prices in particular, some of the rarest cards (like that aforementioned pikachu illustrator card) have been sold for upwards of 100,000$
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.) If the target creature is an illegal target as Persistent Constrictor's first ability tries to resolve, it won't resolve and none of its effects will happen
Many MTG sets include some of these complaints, but this one feels like the most glaring example of this disconnect in its totality