ConstThe toggles are the ribbon's own commands, so they carry the ribbon's icons, tooltips, keyboard shortcuts and protection-disable for free — and pressing one here lights up the matching ribbon button, because both read the same command state. Only the two numeric fields (indent, custom angle) write the model directly: a spinner is a poor fit for a command's fire-once shape.
The Alignment tab of the format pane: where text sits in the cell, how it behaves when it does not fit, and which way it runs.