HTML made for continuous display and re-flowing for different sizes.
ODF is for publishing, i.e. where you can have separate pages, with footers, margins, absolute position inside page (versus whole document), corrections tracking, authorship, figures.
HTML _can_ give you close result, but this is not HTML domain, hence separate standard.
ODF is for publishing, i.e. where you can have separate pages, with footers, margins, absolute position inside page (versus whole document), corrections tracking, authorship, figures.
HTML _can_ give you close result, but this is not HTML domain, hence separate standard.