What I am trying to do with programs like these is to take the mystery out of numerical solutions as well as demonstrate simple Mathcad programs to my students. Many of the Mathcad progams I run in to are so convoluted and involved that it would takes days to figure out the logic. I make liberal use of comments and written explanations. I require the students to do the same. I find that requiring students to actually write code (not done much anymore) forces them to think very logically, many have a tough time at first.
Because 1. Excel has no transparency 2. No ability to lay out file as I chose 3. No ability for free form comments and text . 4. I want students to write code. I use Excel inside Mathcad in some situations. There are a very few problem types where I use Excel on its own.