Classically, because the terminal is a grid of equally sized characters, only a single text size was supported in terminals, with one minor exception, some characters were allowed to be rendered in...
Another thing is that this standard does not allow setting an absolute size… you can only use fractions, for example, 2/3 of normal size, which can still be relatively big if your normal size is big.
I also expect making things bigger for emphasis (or adding headings) would likely be more common than making them smaller (that’s what I hope at least). Outside of things like mathematical notation where superscript/subscript might be useful (see this comment for some examples).
The problem with the web is that some websites use absolute units that might not scale well (like px) to define the sizes.
Another thing is that this standard does not allow setting an absolute size… you can only use fractions, for example, 2/3 of normal size, which can still be relatively big if your normal size is big.
I also expect making things bigger for emphasis (or adding headings) would likely be more common than making them smaller (that’s what I hope at least). Outside of things like mathematical notation where superscript/subscript might be useful (see this comment for some examples).
The problem with the web is that some websites use absolute units that might not scale well (like
px) to define the sizes.