Well, actually they asked two questions... 1) Do even experienced readers read beginner books? and 2) Is it good to read as much as I can about Tarot?♠️
As I’m of the opinion that each deck “family” has it’s own symbolic language (briefly, French, various Italian, German, Waite-Coleman Smith, Crowley-Harris, and all of their derivatives, etc.), I feel it’s important if you are going to use one of those decks, that you have at least a basic understanding of the deck’s symbolic language. Decks in the same “family” may not have the exact same symbolism, but they will generally be close enough to understand, even if it’s heavily “accented”.
Much as a basic understanding of one of the Romance languages may help you to “get along” in another – for example, while in Italy, between my childhood Spanish, my college French and High School Latin, I was able to both mostly understand and be understood by the local people I was speaking with, even though at that time, I had never formally studied Italian.
How do you gain that basic understanding? Read basic books on the subject. So, yes, even experienced readers read beginner books. 
Again, you learn first from basic books, and then expand your knowledge by reading more advanced books on the subject, and put what you learn by reading into your practice.
