The answer for me ended up lying somewhere in the middle, as opening these $1000 lighting rods for debate was a somewhat strange and ultimately fairly anticlimactic experience and I say that having opened two boxes that are probably as close to ideal as you can statistically hope for
None of the tapping requires mana or tapping her, so you can do them on arrival to the battlefield and as many times as you have untapped stuff
Like most Magic: The Gathering cards, the value of Rinoa Heartilly depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Final Fantasy)
Especially when compared to the alternate art used in set four, Ursula's Return, which used darker color palettes and negative space
Oh, and you can force everyone to mill a card anytime you want by a spending a little mana