The good thing about them is it got a lot of kids reading for pleasure, so they might be more likely to pick up something else. The bad thing is that it might lower expectations, making more challenging books less likely to be attempted.
They aren’t as good as CS Lewis. Especially the sci-fi trilogy. They are fairly entertaining, though.
Freegards
Getting kids to read for pleasure is a ‘magic trick’ in and of itself...lol. When my son was a preteen, I bought him the SE swimsuit edition on the condition that he would read all of the articles (just to get him reading for fun). I was desperate...lol. It worked somewhat..he reads alot now, but not much sci fi or fantasy. He is more into biographies,history,politics and other such stuff. Still loves sports and the swimsuit edition though...lol.