The amount of VRAM is the absolute killer USP for the current large AI model hobbyist segment. Something that had just as much VRAM as a 3090 but at half the speed and half the price would sell like hot cakes.
Still some cool hardware.
If your time or personal energy is worth >$0, these cards work out to much more than $100. And you can't even file the time burnt on getting them to run as any kind of transferable experience.
That's not to say I don't recommend getting them - I have a P4 family card and will get at least one more, but I'm not kidding myself that the use isn't very limited.
P40s are definitely the best value along with P100s. I still think there is a good amount of value to be extracted from both of those cards, especially if you are interested in using Whisper ASR, video transcoding, or CUDA models that were relevant before LLMs (a time many people have forgotten apparently).