> But why do reviewers have to do the job of Nvidia's marketing department?
Are you suggesting you would rather read reviews of Nvidia products that are written by Nvidia, and you would trust them more than 3rd party reviews?
> I don't understand Nvidia's marketing at all.
Do read @TomVDBs comments; this isn't Nvidia, this is the industry-wide marketing terminology.
Cores are important to developers, so what you're talking about is that some of the marketing is (unsurprisingly) not targeted for you. If you care most about Blender and games, you should definitely seek out the benchmarks for Blender and the games you play. Even if you understood exactly what cores are, that wouldn't change anything here, you would still want to focus on the apps you use and not on the specs, right?
> I have the feeling they're not; if you're using all Y tensor cores, then there aren't Z unused CUDA cores sitting around, right?
FWIW, that's a complicated question. There's more going on than just whether these cores are separate things. The short answer is that they are, but there are multiple subsystems that both types of cores have to share, memory being one of the more critical examples. The better answer here is to compare the perf of the applications you care about, using Nvidia cards to using AMD cards, picking the same price point for each. That's how to decide which to buy, not worrying about the internal engineering.