Some are cancelled by ISPs with limited newsgroup space, others just roll out of the queue quickly because of size. You are not going to reach many people this way. Many people resent binaries in non-binary newsgroup . All the other messages were hostile. So, if your binary file does survive for a while, it is going to irritate many of your friends in the newsgroup.
Binaries cost some people money .
Newsgroups circulate worldwide. Some people pay by the byte or by the minute to download newsgroups. Many people download everything, then read offline. One single binary can double or triple their expenses for the day. I haven't found evidence of this death-penalty being inflicted on any newsgroup yet, but the fact is that this group exists because of the kindness of tens of thousands of news administrators around the globe.