The use case in this case is the CS1 set of templates. There are at this point some dozen or two of the core templates and then several hundred derivatives calling those main templates (usually).
Rather than store the TemplateStyles on some random template page, it would be useful to store the TemplateStyles in a subpage of the core module, which is presently Module:Citation/CS1. What Trappist the monk has done (not likely knowing better but clearly getting to the Answer That Works) was this history of that style page. That workflow doesn't seem ideal.