A lot of projects don't use it or forget to update it for multiple versions so you probably aren't missing much.

If you use it as a developer you don't care about the releases page. You want to see the code and for latest version you just need the git tags. But I've also used it for stuff I just needed to run on my machine as an end-user. And for those you turn to the Releases page. That's where pre-built binaries go.

But it also depends on the target audience. Some projects, even if meant more as software to run than code to import, still target mainly developers or tech users in general and will not have more than just instructions on how to build them. Others, say a Minecraft launcher, or some console emulator, will target a wider audience and provide a good Releases page with binaries for multiple platforms.