Again, it's not card advantage in and of itself (since you draw three, and then discard three + lose the Coliseum), but it combines famously with Deep Analysis and madness cards (such as Circular Logic), and its effect can't be counterspelled
Tangled Colony probably works best in multicolor decks where you have access to some direct damage spells, or at least spells that force creatures of your choice to fight.
Throw as much mana as you can into it, and it provides a solid body that can threaten immediately with haste, ignore chumps with trample, and defend against retaliation thanks to vigilance
What if they sussed out your plan already
For one, it's a fracturefoil, which any card with that treatment will be worth a lot