However you feel like breaking them down, and whatever mnemonics you do or don’t want to use, what we call radicals are extemely beneficial.
I’ve heard, however true it is - but it feels true - that we can only hold so many pieces of information at one time. But we have a trick. We can take a bunch of pieces of information, put it in a mental box, and then we get to treat that box as one piece of information. You can make several of these boxes, and remember all the boxes simultaneously. You can even put those boxes into another box. And so on.
This is useful to understand. For example, if you’ve ever tried to remember a line in a song in a foreign language you don’t know, it takes a lot of work, because you’re trying to remember a ton of sounds individually at the same time. Meanwhile, in a language you do understand, it’s much easier because you have already
- Clumped some of the sounds together into words. Now you can remember a word as a distinct item.
- Clumped the words into phrases. Now you can remember a phrase as a distinct item.
And you can go on, and have entire lines as items, then go on to memorize the whole song without the same kind if difficulty.
This is particularly relevant to language, as you might see in that example, because that’s how we process it. When we do speak, we’re generally just very lightly remixing phrases we’ve memorized as unique items. There’s very little creativity involved, really, which is why foreign speakers can say things in our language that grammatically make perfect sense but sound utterly wrong to us, because we don’t have a box for that phrase already. That’s just not how we say it!
So… this is my roundabout way of saying that the reason radicals are useful is because it lets you clump strokes (and sometimes sounds) into a single item, and then remember a kanji as a collection of three or so items that you already know instead of as 20 new, individual strokes. A mnemonic is helpful at this point as well, but not stictly necessary.
The other benefit is some of the radicals DO maintain some meaning, especially left-side ones. For example, many kanji that include 糸 do relate to fabric or some kind of continuous thread of time and space, many trees do feature 木, and 打、持、撮、指、 etc all do feature ‘hand’ (labeled ‘nailbat’ on this site), and all have a meaning clearly connected to hands (strike, hold, take, point, respectively)
So there’s that.