I also find that quite surprising. Slowing down “language tutorials” seems like an obvious application, and as JH2013 wrote, such tutorials are quite common these days.
One option is that this effect could be refined specifically for slowing down language tutorials (as described by JH2013), in which case perhaps the name could indicate this use.
Another approach could be a more general tool for “increasing spaces” in a recording, or an even more general tool for “changing the spacing” (longer or shorter).
The thing that we would need to be a bit careful about is creating a “jack of all trades and master of none”. We could end up with an effect that can “Shrink/Expand” spaces (like Change Tempo), “Reduce/Increase” (by truncation/insertion), with choices for % of original silence, % of original (non-silent) sound, seconds, and Expand/Increase options of “absolute silence” or “ambient sound”, but this would probably be too complicated for most uses.
My current inclination is for compromise that is quite flexible, but “specialised” for expanding/extending silence, possibly something like this:
(“Shrinking” the silence could possibly be allowed by text entry)
