There are a lot of reasons someone might want the fastest card. Hosting your own media server and attempting to encode several if not dozens of 4k high bitrate files to multiple users, while still gaming simultaneously is one great example. I am one of those users who think, while yes lower end cards can indeed play most games at 1080p 60fps, that's just not nearly enough for someone like me. I don't even consider myself a power user all that much. I bought a GTX 1080ti several years ago that I have been using. Yes, it's good enough for gaming. However, it is nowhere near good enough to run those very same games on even the cheapest $200 4k 60fps TV. Meaning, you'd need a much better card if you intend to have a living room gaming setup that runs at a constant 60fps high-ultra. Medium settings just don't cut it for a showroom like a family's living room.
Personally, my 36TB raid0 is nowhere near large or fast enough for my storage needs, my 16 4+ghz cores constantly get pinged at 100% sometimes, and my 32GB of memory is constantly being filled. I had an out of memory error just yesterday... I may be a very special use case, but again I consider myself a person on a very tight budget, and I buy most things used, and everything I mentioned is not even half decent enough compared to what I actually think I would use on a daily basis.