This doesn't rule out learn by doing. You can still give some quick helpful tips like "stay away from people when you have the red marker" instead of just saying nothing. People who learn best through practical means aren't incapable of understanding tips.
The great thing about guides is they say everything that happens. But it also means that the viewer/reader sometimes gets too much information, which means it can be more difficult to retain it. For example detailed info about tank swap mechanics are pretty much irrelevant to a dps. At most they would need to know a tank swap exists. Not the intimate reasons for them. If a mechanic affects only a dps that does something like teleport them to another area and they have to do something specific, well that potentially changes nothing about what tanks and healers need to do. Depending on the fight, having to dissect guides to pick out the things that matter to you can take quite a while.
Some guides split things up by role and only inform what that role needs to do in each section, but most I have come across don't. It's especially difficult to deal with an overload of information with a video because you can't really skim through it to find out what -you- need to do like you can with a body of text.
Sometimes guides over-complicate things as well. They might give a tremendous amount of detail as to why someone needs to stand in a particular spot, which can be confusing if the fight already has a lot going on, when telling them "run away from the group when you have the red marker" would be enough. They wouldn't know why they're running away, but after they see a spell effect like an explosion on them happen, well then they end up working out the rest for themselves through practical learning.
A player can strip down a fight to its absolute base and say "healers stand here and watch out for <debuff>, dps run here when <thing> happens" etc. They may not know exactly why they need to do something when a specific thing happens, but as long as they do know that they have to then that is enough. Understanding why will naturally come from doing the mechanics enough times.
That's great if that works for you. But it doesn't work for everyone. I personally have trouble retaining information from videos even if I watch them multiple times. I have to literally write down notes so I can view them at my convenience. However I have little issue recalling something I have experienced for myself even if it's the first time I have seen it. Bosses literally knock some sense into me![]()