Learning with Index Cards

Recently I decided to use index cards in our homeschool for short lessons, as recommended in Charlotte Mason's books about educating children~ homeschooling or otherwise. I bought several packages of index cards, in various colors, labels, filing compartments, and mini boxes for individual use.
 This is no new idea or anything. In fact, I've read other testimonials from parents, in homeschool articles, on how well this worked for them.
 Keeping with the idea of short lessons and doing mostly reading for each subject (using "living" whole books: not textbooks), I have devised a plan to use these index cards with my girls for penmanship, vocab words, written narrations, copywork, geography, nature/science, math lessons, artist study, foreign language, etc. 
 For example, let's say I'm doing a lesson on Van Gogh. I might have them copy his name in their neatest handwriting and write down the name of the painting we are studying, along with a bio of him (depending on age of child). I have also purchased unlined/blank index cards of a larger size for artwork. Perhaps I may have them sketch a drawing of the work we're studying, say Sunflowers, and place in our box. That, along with the book I'm reading on him, and the painting we're studying would conclude the lesson.
 I feel like the index cards aren't so intimidating as a huge piece of notebook paper lying before them on the table, and they can feel accomplished once they are done with their work.
 I like the idea of short lessons on each subject. They seem to stay more focused and retain more from the lesson we are studying this way.
 Another example of this technique is: Let's say I am reading a book aloud to the children and we come to a word in the text that they've not heard before. After I've finished the passage I'm reading, I would go back and after having made note of the words in question, have them copy the word on their index card, labeled vocab words, or color coded, and the definition, and perhaps use it in a sentence the next day on another card of the same color.
 With younger children, this really shouldn't be required. Simply discussing the words together, or by using the surrounding words in the sentence, ask them if they think they can figure out the meaning of the word.
 This can work well when learning about individual states, using a different colored card for each state, with the state's facts. In foreign language, writing down the new word we learn, or phrase of the day. They can also make their own "flash cards" for math lessons. The ideas are endless. 
 We shall see how this goes. I love the flexibility of homeschooling. If this doesn't work, then we can always try something new!