I disagree. Triple Diamonds requires you to grind on the machine for more than 10 hours straight on average.
I once said that and people objected, claiming it would take way even longer. I didn't disagree, but I'd like to think 10 hours is a safe minimum.
Regardless, it is entirely based on luck. I've seen people getting a jackpot from Triple Diamonds after 16 hours. On rare occasions some get it after 30 minutes. The achievement stands for nothing and does not hold a value to those who won after 30 minutes or 16 hours. It benefits no sides and only hurts the completists.
All it represents is "oh something rare just happened to you". The moment is better captured and shown off through a screenshot on a canvas frame and serves no purpose as a trophy to anyone.