Some siddurim have a few opening pages of addendums like how to put on tefillin. I noticed that the Nusach Ari siddur has a page of alef-beis and nekudos, plus a page of letters combined with nekudos. Is this simply an easy way to get a primer in a siddur, or is there another purpose?
I once saw Rabbi Shlomo Goldstein of Diaspora Yeshiva in Jerusalem using such a page in a siddur to show a student the difference between certain letters in the typeface used in that siddur, specifically between a samech and a final mem, and it seemed to me that that it was for this very purpose that these pages are included.
Many siddurim have this, including the very popular Artscroll Hebrew siddurim. In the younger grades, our Rebbeim could use those pages to help teach aleph-beis. I have also seen fathers who had their little children with them in shul use those pages to give their kids something to do/look at during services.
It is a primer for children. First a child learns the alef-beis, then the nekudos, then the sounds of the different combinations of letters and nekudos. It is much like the teaching tool Movo Likriya. It is explained in the introduction to the "eizer" of that book that it was based off the siddur because a siddur is the first real sefer a child will ever use. Therefore it uses the traditional teaching style (komotz-alef: o, komotz-beis: bo, etc.) and uses vocabulary from the siddur to enforce this idea.