Imagine you have a slider control, on some user interface, where the slider lets you go from 0% to 100%. But the slider itself has integer bounds and doesn't understand the percent type.
It seems reasonable to me in such a world where the "0" to "100" is the range of what you get, that it is meaningful to say "but I mean this as a percent".
The question of what TO means--as I've said--is historically fraught. But I've been wrestling with the idea that it's fundamentally reversible, with a principal usage of pushing things "out of band" in a dialect, e.g. where there was already a meaning for the type you were using.
INTEGER! is already taken in your dialect? Ok, to tag! 10 => <10> for whatever other integer-valued idea you have.
Want your number back? to integer! <10> guaranteed to give you back 10, because all TO operations (that succeed) are reversible.
Historical TO has done many things, sometimes along those lines, and sometimes not. Enforcing reversibility and the "triviality" so people could count on TO was the thesis of this post:
Embracing A "Useless" Definition of TO
Working with that idea makes me feel like to percent! 10 would be 10%... for example, applicable in these integer-slider-bar-to-a-percent types of scenarios.