This is fantastic. The LingQ UX is truly horrible and it has way too many unnecessary features, but as far as I knew it was the only thing available with what it offers. I end up paying a monthly subscription, even though I use a very small subsets of its features, just so I can upload ebooks to it.
I've had the same experience with comprehensible input while learning Dutch. The grammar acquisition is what I've found most interesting. I still know next to nothing about formal Dutch grammar rules, but I was able to pass a few B2 practice exams with good scores regardless. I could pick out the correct answer on the grammar questions through process of elimination because all of the other answers just don't feel right. It's also been great for those words and phrases that don't translate well to English. Just by seeing them over and over in different contexts the meaning just slowly accumulates over time without ever seeing it translated or defined.
What really sold me on the method was that learning only through input actually produced equal levels of improvement in my ability to produce output. My speaking and writing skills seem to consistently lag just a bit behind my reading and listening skills. I think it just takes a bit longer to learn new words and phrases at a deep enough level that just come naturally when producing output.