They listed some specific uses. Most of those uses are not good things, but they are specific things that one could do with them, including more tailored spam campaigns. I think what you're asking is why you would want to use one, and it sounds like the answer is you don't want to and you don't need to. I don't need to, and I probably won't, but if I did, it would be to play around with it, not to do something particularly useful.
That said, I can see some situations where some models could be more useful to the average user. For example, there are text to image models that sort of work. Sometimes, they end up making weird, illogical images and sometimes, they don't even get that far and make images that are a bit more horrifying, but sometimes they also work. I cannot draw. If I decided I wanted a picture of something created, running a bunch of prompts and seeing if I could get the computer to spit out something good enough might be a faster or cheaper way of getting the image than commissioning someone with real art skills to do the job. This is not something I'm going to do any time soon as I have not needed an image created, but it is a case where I could see someone deciding that running a local model sounds like a good idea. I don't know how good the local versions are, so they may be disappointed with the results, but the decision to try it could be logical.