It's practical for the market Alvo is targeting: coffee-shop, personal magic that makes a lasting impression on a person. It seems to work very well in that situation. I can see what you mean about impracticality, but I don't think it was ever meant for that venue.
yeah, it usually only uses one person. If all magicians started using this effect, so many people would be amazed, not just one person, but sometimes you need to stop performing for an entire crowd and just perform for one person. Every weekend I do this. I work on tips at the swap meet. (I'm fourteen, I really have nowhere better to be...) Anyways, performing to one person at a time, sometimes two, ends up being a few thousand throughout the 8 hours I'm there. I usually only use one trick, unless they ask to see another. (The B2 Bomber. It usually gets me a tip if I do it with their dollar...) Anyways, sorry for getting off of the right subject... but yeah. you have to perform for ONE
person sometimes. (Not saying that stage shows or multi peopled tricks are bad though...)