The E stands for "Enterprise", so there's a hint about the target audience. You can get support for a 10 year old RHEL version after you entangle it to your stuck in time IT infra :)
More accurately, it's a synonym for "Allows my line-critical COTS to run predictably"
If you're not in a tech business, and are therefore using other people's software, then you want to be on the same platform that they were during development which would have been years ago. If it's Linux, then it's something like RHEL.
