Disclaimer: it’s about learning Japanese. Whatever method works for someone, works. I’m not saying other resources are bad, just repeating what CureDolly argues to answer the question about her methods. Jump down her throat if you disagree, not mine. 
She argues that many resources try to cram Japanese grammar explanations onto a framework of Western grammar, while this doesn’t quite fit.
This causes a lot more instances where certain patterns that JP has aren’t explained well, or are reduced to “that’s something you’ll just have to memorise,” while Japanese is in some ways a beautifully modular language. She equates it to Japanese being like Legos. When you have the blocks and know what they do, it’s very doable to slot things together.
A few random examples; how it’s much easier to ignore the notion of “Japanese conjugations,” and instead look at it as the stem system it is. She also covers transitivity in the Japanese way, as self-move and other-move verbs, in a manner that clicks very well with people. She also argues how the way certain forms (like passive and causative) are explained in a manner that can cause confusion down the road.
Personally, I feel like every claim she makes about such instances are well-reasoned, and she shows fair examples of how learning Japanese through the lens of Western grammar can sometimes be a bit convoluted. She doesn’t claim other resources are terrible - just that they can at times make learning Japanese needlessly confusing.
I think her channel can be a great addition for anyone, even if you’ve already gone through a lot of the very foundational stuff. ^^ Really interesting stuff there, and I personally found it all much easier to remember when I truly grasp the how and why of it, rather than sit there and try to drill grammar facts into my brain through rote memorisation.

Seriously… English grammar as well as grammar in my native language - I can use it, but I’d fail elementary school tests where you’re supposed to " dissect" a sentence and name all the grammar constructs at work there.
I barely know this stuff in my native language, let alone English.


