So, I played WiiU more than I played 3DS. I didn't think that would be the case. Plus, 3DS was only a little over 500 hours, with Ocarina of Time as the most played game (2 playthroughs, one 100%, plus some random meddling) with 99 hours. Majora's Mask comes in with 53 hours, with a single 100% play through. Mario Kart 7 is at 48 hours.

For WiiU the obvious winner is Breath of the Wild with 241 hours. Beating Super Mario Maker with 158 hours handily. It's just one playthrough (all Shrines and Divine Beasts, about 400 seeds), though including the expansion pack. I also didn't expect Art Academy would be #3 with 99 hours, but there you go. I think Mario Kart 8 isn't that far behind. I'm guessing the two games next to the genres are just the last two I ever played of those genres.

Someone broke this thread... scared to post here.

I gave my WiiU to my family and apparently all they did was watch Netflix and LoveFilm.

MK8 with 177hrs and Splatoon with 104hrs are the main reasons why I didn't buy MK8D and barely played Splatoon 2.

... and also 149 titles, didn't know WiiU had that many xD

Evidently I mostly used my WiiU to play Netflix and YouTube, with Mario Kart 8 securing the third spot at 212 hours. Scram Kitty and his Buddy on Rails somehow gets a top spot, which seems kind of crazy or even wrong. Where's Lego City Undercover, I'm sure I played that more than Scram.

It couldn't detect my 3DS.

Most of that Netflix and pretty much all of that Amazon time is the rest of my household's. That Wii U was our main streaming machine for over four years.

It only goes up to late February 2020.  So if you were playing it after that, none of that data would show up.