What is the new feature or improvement?

Other modded UI buttons like the "sort" button, Attributeslib, etc. get hidden when The curios tab is enabled.

An option to disable this would be quite nice.

It's not that they get "hidden", it's that they don't get added because the Curios inventory screen exists separately from the regular inventory screen. It looks similar, but it's an entirely different screen and so does not inherit any elements that a mod adds specifically to the regular inventory screen.