>despite her spending 10-20 hours/week gaming

Pardon the wall of text here...

I typically spend 40+ hours/week gaming. Literally a 2nd job. However, I don't even consider the time spent gaming in my definition of "hardcore" gamer. There are people who play 80+ hours/week that I would consider "casual" gamers by definition of how they play. They see games mostly as a way to kill time and might identify the activity with being a hobby, but not one they take "seriously" to any extent.

The thing that makes me "hardcore" is the amount of time I don't spend gaming - but learning about the game on a deep level. I typically have 99% of a games' wikipedia memorized. I can tell you nearly anything about any of the games I play off the top of my head. I'll know every mechanic, every bug, why the bugs exist, a summary of the lore. Depending on the genre, I'll know the best places to level at any particular level range, where every single enemy spawns (or whether their spawn is random), the damage output of every weapon in comparison to one another, how certain items scale, the frame data of certain attacks (eg: first hit frame, ending lag, if it has invincible frames, the number of end frames).

Casuals don't care to put in all this extra effort to know the game on a deep, often very mechanical, level. "Intermediate" players will read about it but still don't invest much time to it. "Hardcore" players know a game inside, inside-out, upside-down, mirrored, and can probably run through some levels blindfolded going off their memorization of the game alone.

A casual player can play SSBM for 30 hours a week without ever learning how to wavedash, L-cancel, chaingrab, wobble, (S)DI, amsa tech, moonwalk, shffl, platform cancel, slide cancel, soft B-reverse, or ledge stall. There is also a good chance they think I made up half of those words or just said some random things. They also don't tend to keep up with any metagaming - or if they do - they're never on the forefront of innovation for the metagame, but only ever (poorly) copying what they see pro players do without understanding why the professional player made their decisions. The casual player's mechanical knowledge about the game is lacking too much to effectively innovate because they don't really understand how the game interacts with itself.

My casual League of Legends coworkers' are all ranked Bronze/Silver because ranking in that game is almost entirely a measure of knowledge and only a very small part of it is skill - they all play the game far more than I do but I understand the game better than them and ranked among the top 1% of players (Plat1/Diamond5 range) when I played. They never cared to learn about the game itself - so never improved as players. Even after months and months of playing with them they never got any better at the game, even as their general "skill level" (ability to execute) was increasing over time. Certain games also lack depth - and are the games I consider targeted towards casual players. Most of those are mobile games like Angry Bird, puzzle games (eg: 2048, Candy Crush), or arcade-like games like Pacman, Asteroids.

So while I don't consider playing puzzle games on an iPad "not real gaming" it is also very much a sign of "casual gaming" - it's a time killing activity. Without knowing your wife, I have my doubts that she spends a significant time metagaming her puzzle games or researching the best way to solve the puzzles. This is partly because that would be counter-productive to a good puzzle and partly because there often isn't enough depth to a puzzle game to research about it.