If the card leaves your hand, it's too late: If your Miracle card happens to get bounced, exiled, discarded, or otherwise removed before the triggered ability resolves, tough luck, you can no longer cast it for its Miracle cost
I myself have walked to the Panopticon, spent my entire turn tapping out, drew three or four cards total and we left
Instead of racing to 7 mana for Titan of Industry or 10 for Ulamog, the Ceaseless Hunger, you want as much mana as possible to pour into cards like Wan Shi Tong, Librarian and White Sun's Zenith
Youre basically stealing cards from the top of their library while making elves and faeries
The big problem is that five mana Equip cost later down the line
This particular card allows the caster to remove the restriction on hand size, and draw cards instead of gaining life