It's super effective!
It's about 1g of material and prints in 2,5 minutes at 0,2mm layer height. So effective.
You like reading a lot of books? 3 or 17, all at the same time? Then this is a solution for you as you can cheaply and quickly print a ton of these.
Think about the many spools with some filament remaining on them that isn't enough for a regular print but also kinda hurts to simply throw away? Make effective use of that material by manifesting bookmarks!
It's a simple design but right on point, literally! You can use the pointy end to indicate where you left off reading.
Happy printing and remember knowledge is power! And knowledge can be found in books, sometimes!