2) Bound Imp may be played as an Ally or as a Monster? That is really something strange. Apart from some Class deck characters that like to have Monster cards in hand and circumventing any "when you play an ally" effects, what are the possible uses of that? As the Bound Imp just draws cards, it is probably not meant to sidestep the "1 card of a type played on 1 check/step". Any insights from the community? :)
Can't comment on the first question, but the second one is purely for Class Deck and older set synergy (specifically with Summoners). The Summoner Class Deck (and Ultimate Magic) featured a series of allies like "Bound Elemental" and "Bound Lantern Archon" and even a pre-Core "Bound Imp" (I think) that all could be treated as monsters, and all could be recharged with Arcane checks.
Keeping the same design space - even though it doesn't really impact Curse play if you're not using old sets/decks - seems flavorful and practical. Especially since, in Organised Play, you're allowed to replace 'old' cards with the same-named 'new' cards, and you'd want to keep that element.