As I argued at length in my response on your last question, I'll argue that making it easier to gain a natural cubic spline fit is not necessarily a good thing at all.
https://www.mathworks.com/matlabcentral/answers/325706-natural-spline-unmkpp-gives-wrong-answer
Were that to happen, then we would find too many cases of people having problems with the spline fits they get, and often not even knowing they were using the wrong tool to solve their problems.
So, it is indeed possible to gain a natural spline fit to your data, and you can find it, IF you look. I showed how to do such a fit in two distinct ways using the existing spline tools.
But making it more obvious and easier yet to build a natural cubic spline will only give novices (who do not understand the issues and the reasons to avoid them) the wrong tool to use, and the comfort of thinking they are just using what they were taught in some long forgotten class.
I'll argue that this is the same issue as with det. Det is perhaps the most misused tool in MATLAB (with inv in second place.) That happens because it is there, easy to find. Students are taught to use a determinant to test for singularity of a matrix. But those same students are rarely taught why they should avoid using det after all, that other tools are a better choice. My point is, had det been provided only through some less obvious source, we would have fewer problems. Yes, det is here to stay, as is inv, but lets not create another det.
