It seems like a powerful technique, but I’m confused about when to use it against just a PAO system or something. For example, if I’m trying to learn massive amounts of vocabulary, am I going to be able to quickly take the whole journey each time I want a word? What sort of situations is it best for?
First of all, PAO is often used in conjunction with the Method of Loci. PAO is a method of assigning images to numbers and cards, whereas the Method of Loci is a method of placing those images in a familiar setting so that you can more easily remember them and the proper sequence.
That being said, I think learning vocabulary is one of those challenges that is better served using direct association rather than a Memory Palace (Method of Loci). Create an image for the word, then create an image for the definition of the word, and make those two images interact in a memorable way. You don’t need a Memory Palace to do this. Memory Palaces are best used for instances where you must remember a sequence properly, such as the order of numbers or the order of playing cards, or the order of random words, like a list.