In the Sonora, chiltepin is basically a marker of cultural identity - being from there, it's a basic ingredient. Similarly, in Texas, the "chilipiquin" is *the* state spice.
In local cuisine, chiltepin is, of course, used in a variety of dishes - in its green form, but especially when ripe, both fresh and dried. One simple usage is a good example to the chilehead: Carrying a tin of dried chiltepin as emergency supply to spice up all those things which need it. Chiltepin pods are also added to vinegar or sherry to produce simple flavorings.
Chiltepin might be a good diet product: Capsaicin heightens metabolic activity. Of course, using those little beasts like some Mexicans do, as a replacement for sweet drops, one would also have other concerns than the next meal (and get more vitamins A and C than from fruit juice).
On the other hand, chiltepin has a long history of use as a "drug" that improves appetite and supports digestion.
Already among the Aztecs, chiltecpintli - derived from the words chil-/chilli and tecpin: flea (because of the small size and the strong "bite") - a kind of pepper that was commonly used. Interestingly, one of its forms was called totocuitlatl - "bird excrement." Pretty observant, considering the chiltepins' ecology.
ChiliCult.com - Chile Peppers and Culture