Going to go out on a limb and guess that it's because the people who would actually go through these tutorials are people who already know what can be accomplished with raytracing and want to get their feet wet with doing so in Vulkan.

The average person who's looking for "What can raytracing do for me" is going to get their answer from Control, Battlefield, Metro Exodus, or even the Quake II and Minecraft demos, and not some developer-centric Vulkan tutorial from Github.