As I do not play standard or modern I'm not sure how advantageous building around alternate win conditions is for those formats but I do know a bit about EDH. In cEDH almost all competitive decks win by either milling yourself out and casting Lab Man or milling your opponents out and letting them lose when you pass the turn to them. The reason for this is that most of the time creature decks that focus on beatdown just can't race these kinds of combo decks. Most cEDH decks win through assembling an infinite mana combo of some sort. Now while you could use this mana to cast powerful creature cards like Praetors or Eldrazi Titan's most of the time they're affected by summoning sickness and, although there are ways of giving you're creatures haste, cards like those tend to be dead outside of this specific situation. Its preferable that you win on the turn you go off and don't just pass to someone with a scary board just asking to be Cyclonic Rifted or something. The only common combo/deck I can think of that wins through creature beatdown is Ruric Thar Stax. Mostly this still involves assembling a Kiki-Conscripts combo with only works because they have haste, or locking the board down and going for Ruric Thar beats. This only works because either it is unexpected, i.e. Kiki-Jiki, or you're opponents aren't able to do anything about it because you played Blood Moon and who actually plays red in cEDH?

As I do not play Standard or Modern, I'm not sure how advantageous building around alternate win conditions is for those formats, but I do know a bit about EDH. In cEDH, almost all competitive decks win by either milling yourself out and casting Lab Man or milling your opponents out and letting them lose when you pass the turn to them. The reason for this is that, most of the time, creature decks that focus on beatdown just can't race these kinds of combo decks. 

Most cEDH decks win through assembling an infinite mana combo of some sort. Now, while you could use this mana to cast powerful creature cards like Praetors or Eldrazi Titans, most of the time they're affected by summoning sickness and, although there are ways of giving your creatures haste, cards like those tend to be dead outside of this specific situation. It is preferable that you win on the turn you go off and don't just pass to someone with a scary board, just asking to be Cyclonic Rifted or something. 

The only common cEDH combo deck I can think of that wins through creature beatdown is Ruric Thar Stax. Mostly this still involves assembling a Kiki-Conscripts combo, which only works because they have haste, or locking the board down and going for Ruric Thar beats. This only works because either it is unexpected, like Kiki-Jiki, or your opponents aren't able to do anything about it because you played Blood Moon and who actually plays red in cEDH?