"Festum" versus classic \section with titleformat of titlesec

[MRoth1910]

\titleformat{\section}[display]{\huge\filcenter\sc\addfontfeature{LetterSpace=5.0}}{}{}{} is not quite the same as this:

\NewDocumentCommand{\festum}{m}{%
\needspace{5\baselineskip}%
\vspace{\baselineskip}%
 {\centering{\LARGE%
 {\MakeUppercase{%
 {\capspace{#1}}
 }%
 }%
\par}%
 }%
 }

Manipulating this command to match the titleformat (or vice versa to save space) would make section useful for the beginnings of subfiles (the major divisions: Christmas, Epiphany, Easter Trinity without having to resort to addcontentsline and phantomsection especially where we don't need sectioning (Ascension, Pentecost. Corpus Christi, Sacred Heart in the temporale and the double of the I (II) class feasts in the sanctorale) or where we don't have feasts (the Saturdays of the temporale before the first Sunday of the new season) because the anchors are hard to get right.

(Also remember with festum, we can type normally and then the MakeUppercase should do the rest.)

[MRoth1910]

Using \section*{} will result in that specific text be displayed the same as a section heading, but no other feature of section (no section mark for headers/footers, no ToC entry, and no number).

another consideration for where we want section commands (whether or not they're in the "Index Generalis").

and the titlespacing possibility is also related (titlespacing on TeXSE)