An ability that triggers "whenever you tap a creature for mana" triggers only if you activate a mana ability of a creature including in its cost
Imprinting the card is only a minor drawback, considering that you've already gotten your use out of cards like Devourer of Destiny from your hand, and you play enough copies of your others like Ugin, Eye of the Storms that it's not so bad to lose one
If you find a more interesting card, feel free to leave it in the comments section

EX Power Trio Tin [Blastoise EX] $424.99 Red & Blue Collection [Blastoise EX] $995.63 XY Evolutions Elite Trainer Box [Mega Blastoise] $601.26 XY - Evolutions Pin Collection [Mega Blastoise] Battle Arena Deck [Mega Blastoise] Battle Arena Deck [Mega Blastoise & Mega Charizard X] V Battle Deck Display [Venusaur V/Blastoise V] $158.95 V Battle Deck Bundle [Venusaur V/Blastoise V] $59.70 Blastoise #2Holo Rare $224.86 Blastoise #2Holo Rare $820.00 Blastoise #2Holo Rare $150.80 Blastoise #1Rare $100.00 Blastoise #14Rare $17.54 Blastoise #2Holo Rare $95.08 Blastoise #2Holo Rare $49.04 Blastoise #13Rare $14.26 Blastoise #31Holo Rare $8.62 Blastoise #137Secret Rare $464.98 Ariados #7Uncommon $0.14 Wartortle #16Uncommon $0.19 Meltan #45Common $0.12 Ambipom #57Common $0.14 Slowpoke #19Common $0.18 Radiant Blastoise #18Radiant Rare $11.47 Bulbasaur #1Common $0.25 Spinarak (Peelable Ditto) #6Common $13.70 Mewtwo VSTAR #31Ultra Rare $7.14 Charmander #8Common $0.23

You have counterspells, kill spells, sacrifice outlets, copy effects, mill strategies, and zombies all under one roof