Maybe I'm wrong and this is new to a lot of people! I have a limited perspective based on my programming journey, which winds mostly through gamedev, graphics programming, and DSP, both (typically) low level domains. But I think if the title if the article were more accurate, (e.g. "What are pointers?"), my reaction would be more clear. I'm also kinda taken aback by the "old grey beard" comment. Look at all the kids using Rust, Zig, even C and tell me that this is obscure knowledge.
When I took my first programming class at RIT, visualizing the stack, variables, and pointers was one of the first classes we had. It's one of those beginner diagrams that I feel like everyone is familiar with. But I can understand that there are programming domains with equivalent complexity which don't require that base knowledge. I apologize if I came off as elitist.
