I see, but in that case you would have to change the code anyway, if the label is changed from "ok" to "maybe" then the constant will also change to this.MAYBE. In reality there is no reason to change "ok" to any other label unless the semantic value of the button changes but then the code is not doing what you intended to in the first place.
I think the renaming advantage only exists when the constant value tries to hide an implementation detail like a number or a code.

In montage we haven't been using constants for strings, for instance, the translate-composer uses `"both"`, `"horizontal"`, `"vertical"` for the `axis` property, among others.

Having said I think a constant is probably still useful for IDE purposes, will change for what François suggested.