Yes, I bought Amiibo Festival but I never bought a WiiU. It was just cheaper to buy it for the Isabelle and Digby amiibo figures and the Rosie, Goldie and Stitches amiibo cards.
I still have the game somewhere, keep forgetting to give it to the charity shop.
The closest I've gotten is buying games for systems that I have bought but just haven't arrived yet, yano, so I have something to play once it arrives.
I don't really see the point in buying a game for a system you don't actually own and don't see owning in the near future. It's highly unlikely the game will become unattainable once (if) you get around to buying the system and chances are you'll even get it for a lower price by that time. Seems like a waste of money.
Does it count if you could technically play the game but it's for a different console? Because I found a copy of the original PlayStation version of Mortal Kombat Trilogy when I was out of town when I was a kid and bought it. I could technically play it on the PlayStation 2 because of the PlayStation 2's backward compatibility feature, although it did tend to black screen if you managed to beat the main game so it wasn't perfectly backward compatible.
I bought Skyrim when I knew my computer couldn't run it because it was on sale on steam, so now I have it on my new computer that I can play it on, I bought it at least a year or two before having a computer that could play it.
i got close to buying amiibo festival even though i dont and never intend to own a wii u. simply because it's on sale for so cheap, it's actually cheaper to buy the full amiibo set with the game than the two amiibo separately.
I've done it once, by accident though. I brought a few games, but one that stood out was life is strange for the Xbox one which I don't have. I kinda freaked out about it. But heck, it came with the sound track so I was happy