What if I don’t want to follow the real stroke order? Does it matter? Like, for example, to write 必, I prefer writing 心’s stroke order and then put the ノ. Is that incorrect? Why? My apologies if that’s explained laterly.
Personally, Its a whatever. I mean not every person writes the English letters the same even though there is an official way to write them so I don't think it should matter they much in Japanese kanji.
Although your efficiency might decrease of your preferred stroke order isn't optimal
The answer to your question very much depends on your reason for learning how to write. Are you learning kanji to read, type, or casually write for yourself? Then stroke order is mostly optional.
I've heard it helps with memorisation, but that might be more of a consistency thing, rather than the correct order itself.
For calligraphy or any formal handwritten art, Japanese school, or preparing for tests like Kanji Kentei, it very much matters.
Anyway, I'm sure someone with more writing experience can give you a better answer.
It may affect the ability of writing input tools to be able to figure out what you are writing. Some are expecting a specific stroke order, and mixing that up may make it harder for it to tell what you are doing.
For handwriting (not on a computer), if you write slowly and legibly you should be okay, but as you start to write kanji more quickly, they start to look more like scribbles, and then readers will tend to rely on the stroke order to interpret what those scribbles mean. But if you don't stick to the standard stroke order, that makes their job harder.
So, using the standard stroke order has some advantages, but you can probably get away without strictly sticking to it.
Can't speak for everyone, but getting the stroke order (and direction) right helped me correct some kanji that came out badly proportioned in my handwriting. And, as Anonymous123 said, it may not look like much while you still draw the kanji tidily, stroke by stroke, but once you get into a more "flowing" handwriting, it can really make them hard to recognise. (Kind of the way, in European countries that use cursive, some people's writing is a nightmare to decipher because they've never bothered to learn to cross their Ts and dot their Is.)
Stroke order and direction also helps me mentally separate their components and categorise them with "fellows" of similar radicals. That said, this is important to me because handwriting helps me immensely with remembering kanji. If you intend to hardly ever write kanji by hand, I don't know if it's that relevant. But otherwise, I figure there's a good reason why they've been doing it like that and not differently for a few centuries.
