This can trigger nicely additional times off stuff that causes attacking to trigger more or more combats, which lets you really leverage the ability and get the number of quest counters up really rapidly to dangerous levels
I'll do my best to flag some underrated cards - but no promises
Eluge, the Shoreless Sea and Xolatoyac, the Smiling Flood are some commanders that actively use flood counters, though you arent always as likely to have a merfolk to get that card draw
Not enough card draw Without 8-12 draw pieces, you run out of gas around turn 6 and stop affecting the game
The rate isn't bad for what you get, either, and the Great Train Heist will be useful at every stage of a game, whether you're using it for an early mana advantage, as a combat trick (offensively or defensively), or as a source of extra damage to close out a game
Combined with Grapple Shot , damage spells, and various weapons, this avatar can dominate the game while giving you card advantage in the process