Use of <hi> and @rend='sup'

[lb42]

1. Every occurrence of has a @rend attribute, so should this attribute be mandatory?
2. Only two different values are currently supplied for @rend in the data: "italics" and "sup"
3. There are only 10 cases of sup, all of them within a where they should (probably) better appear as a
4. If this were done, and hence no value other than "italics" ever envisaged, why supply @rend at all?