Simple the OP meant would mean that it's easy to understand/digest for all -even beginners- some books can be so cumbersome or professional for beginners to get understanding on, I suggest every beginners should go for beginner's book on crytocurrency
Block explorers are one of first places to start in crypto.
(Compilation) What is the best Ethereum explorer? (already 21 reviews!!!). That thread brings to us reviews on 21 Ethereum explorers.
I just read the article and yup he tried to explain it to people who didn't even know blockchain and crypto. He tried explaining it by comparing it to renting in a car company and etc. Try reading it and you'll understand why its called simple. Any technical topic can be explained using simple terms. That's how I learned btc and crypto too. If I Jump right away to the technical terms, I wouldn't be here cause technical terms bore me. I have to understand it first in simple terms.
Technical terms in crypto almost kill most of people at beginings. It is true for non-tech gurus and not all of us can be a tech gurus, at beginnings or at the ends after progress of reading, learning, and experiencing. Start with simple descriptions or explanations to get motivations to move further for in-depth learning on technical aspect.
In crypto, people must learn about some very fundamental technical terms and related use cases or tools. It will benefit them in the long run and also help them to discover scam projects and save their capital.