It’s an assisted reader. It allows me to read any content I want to (except for physical books…but it can do that if you have patience and time). It’s very easy to import a lot of different content, whether it’s from youtube or the web or importing e-books.
It allows me to choose from a wide variety of online dictionaries to get meanings (you aren’t stuck with a single dictionary that might give you the wrong interpretation).
Now, with whisper it can add a transcript to imported audio files. For German and Spanish this works quite well. (May not for other languages so ymmv).
Another cool new feature is the “simplify” action. I was doing something like this using chatgpt, but it’s nice to have this feature built in.
It has great stat keeping. To me, this is one of the most important features. When you feel like you’re making very little headway in the intermediate levels, your stats will show you otherwise. If you have a strong perseverance you might be able to keep forging ahead using other assisted readers, or google translate extension, but I think most people don’t have that willpower. I do somewhat often read outside of LingQ using that, if I just want to quickly peruse something, but usually I do import it.
Anki - SRS…I don’t use SRS in LingQ or other apps. Initially I did do some in Memrise for German awhile back, but my progress in LingQ has been FAR quicker.
calibre + translator - I have done this to see how it worked (albeit a few years ago). It was ok. Yes, easier on the eyes for reading I’ll agree, but as an assisted reader, LingQ is better (for me) - multiple dictionaries, stat keeping, PORTABILITY is a key one here too with the apps for phone and tablet. Can’t do that with calibre. I do most of my reading not at a computer.
language reactor - great tool. I use it for a lot of my movie/tv show watching on Netflix. On youtube I find it too clunky, but have it tried it there in awhile.
readlang plugin - haven’t tried this. i think I’ve heard some good things. If it can help record the stats in readlang itself then it sounds great. If not, why not just use google translate extension? I do hope in the future LingQ could do an extension like this that would record the words in the application (and the stats).
duolingo - I’ve used in the past and generally think it’s ok for beginner stages. It will not help you very far though. I also think you’ll progress much faster doing reading and listening.
So, the key things to me that I don’t think the other things beat is - flexibility in content choices (i get to choose from nearly anything), stats, great choices for looking up meanings, portability.