I say go for it @TGW, the market is always open for assets to use. Cheaper knock offs would be great as placeholder art to test game mechanics, animations and temporary art. There isn’t really a demand for priced assets, but also you can say the same about premade assets at all.
But like I was saying earlier, having a full game of assets really helps to practice a making games. I’m sure many of us would probably purchase a pack for Super Mario Bros. (Nintendo copyright) for $10 just to see what it takes to recreate it.
Also to mention, the old packs that was available in the Flowlab store were space themes at around $30 each (which let’s be honest, not even me would try to purchase at that price). And finding non-free art or packs for a game on itch.io can vary around $10.
But yeah, go for it. If it seems useful or something I could use for a game, I would look into buying something like that for sure. Baron’s sprite pack was a great test for me to see what it would take to make a platformer (which I re-used the code for Dungeon Platformer).