I also use the "send to kindle" chrome extension which takes the web page page you are looking at and sends it to your kindle.
I find it really useful for long reads I need to pay attention to and I like having a queue of them on my kindle.
https://chrome.google.com/webstore/detail/send-to-kindle-for...
I think the issue is with scrolling itself. Scrolling erodes the attention span because it kinda goes against the grain of saccadic perception. As opposed to that a page turn on a physical book transitions to the next page and stays there in a state of rest until we have comfortably absorbed all of the content on page and are ready to move on to next.