Do meshes have to be connected? I'm new to Blender and I was wondering, do meshes have to be joined?
In the image below, I found it a lot easier to just snap the edges to the top face instead of joining all the vertexes. Is that a correct way to do it?
It depends on your use-case, but in general, no, it's not necessary for meshes to be connected. A good rule of thumb is that if the object is composed of separate parts in real life, it's okay for its model to be made of separate parts.