Shouldn't people who want to learn web development use the workflow and tools of professional web developers? And since these tools are free, I don't see the case for Thimble.
As a professional web dev: dude, this is what I wish I had five years ago. Categorically no: teach people using the fewest amount of tools needed to get cool shit written and working. Then, when they hit the limits (IF they hit the limits) of that single "get shit done" tool, have them branch out to the more complex stuff.
Installing and setting up all of those tools takes time and effort, and there usually aren't great step-by-step guides for "Here's all the tools you need and how to set them up to work together".