I am in Adoby's camp.
Basic fonts for the body of the work.
Occasional 'Fun stuff' done to Titles, Headings and first Paragraphs
I detest books that have been
stripped of all typography just because someone
else might want to read them on a 2 inch phone screen.
I also detest huge (>10%) top margins for all chapters.
My goal
1) Readability on typical, mainstream usage READING devices
2) Visual Balance on typical (5-7") dedicated devices , not the size extremes.
3) Varying base style. No OSFA, cookie cutter styling. BUT I do normally want uniform styling within a series. They are a series and should follow a theme once--if any was started.
4) occasional use of fleurons and other embellishments.

Isn't that what the paper edition book designers have been doing for decades? Maybe they are on to something