Great article.
I didn't start using knee sleeves until I got old. Especially when it's cold in my garage, I really appreciate knee and elbow sleeves. Still, I don't use a belt or sleeves until my last warmup.
Stoic sleeves (like the ones in the picture in your article) are almost as good as SBD ones but at a much lower price.
I don't know the rules for each federation, but in the ones I'm familiar with knee wraps, unlike knee sleeves, aren't permitted in raw competitions. As someone who competes without a coach, I find that knee sleeves are easier to put on than wraps.