"Hi Mark. I just read your comment, and since I was one of the users Rain is referring to, I thought I should weigh in. I think that your point about the value of the alignment rather that structural integrity being the real value is partially right, but you're wrong about the part where you say it doesn't contribute strength. There are many types of woods such as Teak, or Cocobolo that are very oily, having more surface area to glue to is valuable. There are also a number of very porous woods that soak up glue a bit more that others. These types of glue ups can absolutely benefit from having a tenon in it. Think of it this way.... you can increase the surface area where the glue contacts the wood by double if not more by using the Domino. Biscuits are sloppy, and don't provide the same strength when being glued. When all said and done, isn't it more valuable to have a tool which provides great alignment as well as structural integrity you can count on?"