It can display PDFs, but the screen is small and I find some technical PDFs have diagrams that when shrunk onto a 5" screen become undecipherable. A screenshot from a tablet may look ok (I don't know if any Kindles have color as opposed to grey-scale - mine doesn't, so that could be an issue) but I suspect screenshots of a 24" screen might appear a bit too tiny. Tables and code samples, like diagrams and screen shots, are going to be OK only if they fit legibly onto a 5" screen. So I don't think that a Kindle is is adequate for all technical books, only for some.

Also sometimes when with a paper book I would keep a place with my finger while I looked at some other section the Kindle equivalent is any one of add a bookmark, remember some text (then you can search for it), or remember a position identifier (a number, how many digits depends on how far into the book the position is). At first I found that awkward, but I've got used to it and creating, using, and deleting marks has become easy. And of course when you close a book the Kindle remembers where you were, which is something I've often wished paper books would do.

I find mine useful for some technical documents but not for others because of the problems with the 5" screen. For the others I use either the Kindle app on my laptop or Foxit reader (both are free, and I hate Acrobat) or other apps for other formats (most formats can be converted to Kindle format or PDF). I've run out of shelf space so I have reduced by paper book acquisition rate by a large factor.