I got the impression that kind of thing (buying time on GPUs hosted in people's homes) isn't useful for training large models, because model training requires extremely high bandwidth connections between the GPUs such that you effectively need them in the same rack.
I suspect most A100s on vast.ai are actually in a datacenter, and might even be on other public clouds, such as AWS. I don't see why either vast.ai or AWS care if this was the case.
