They don't. Removing these tags will not result in any meaningful increase in page load time honestly. This is especially because most don't actually load up any linked file. Their weight is just the characters they are typed out in.

It's an informative webpage but it's not very effective optimization imo.

Well, each byte is one I guess? At least before compression.

Reminds me of a colleague who argued for tabs over spaces, because it saved bandwidth.