Most of those paintings in that Art Exhibition were several centuries old. The latter half of the definition about appreciating them primarily for their beauty or emotional power I think is when you start stretching the comparison thin - but consider this: have you ever looked at a deck and thought "Wow that's super cool" or been struck with awe? Or looking at deck lists from a metagame past (or present) and associating certain feelings or emotions with them? In Pokémon, you get to choose 60 cards to compose a deck and there's so many possibilities - this is that first part of the definition around creative skill and imagination. Even if you do something like play a board game, most of the time you're just following the rules and you have narrow avenues for expression (usually all the participants are doing the same thing and you have a finite amount of choices/control).
Pokémon Deck Building, even as an engaged enough fan to want to read about it on Reddit, is a really abstract thing that's difficult to compare other activities to. My thoughts about this are something I cobbled together into a short video on my youtube channel and I wanted to share it - usually I do things like deck profiles, but I made this video more to provoke thought and mainly to entertain: (Oxford Dictionary) describes art as "The expression or application of human creative skill and imagination, typically in a visual form such as painting or sculpture, producing works to be appreciated primarily for their beauty or emotional power." I think you can apply this to Pokémon Deck Building too.
Since competitive Pokémon Cards is something I think about a lot, I inevitably got to thinking about how a lot of the thoughts and ideas around creating art can apply to Pokémon Deck Building too.
I've been thinking about Art recently between a visit to an Art Exhibition titled 'European Masterpieces' and watching the anime 'Blue Period' which does a good job of describing how to think about creating artworks (especially Paintings).