Red cards do enough with artifacts to make Krenko, Baron of Tin Street an interestingly intersectional red commander, combining artifact and goblin synergies into one package
It is better to buy the 690 Poke Gold bundle if you want the best value for your money
Being able to make an opponent sacrifice a creature can, on turn two or three, leave them with nothing to attack with, helping her stick around for longer
To get good returns on this it is really a five drop card you immediately follow with a land, ideally a sac land
This means it's not possible to cheat creatures into play out of nowhere (which madness can do), but it also means you're granted more flexibility, because you can cast a spell for its mayhem cost at any point during the turn in which it was discarded (rather than having to choose immediately as per madness rules)
The choice of the creature happens when the trigger is resolving, so there is no way to respond to that choice