This is the typical way of talking about “more useful than” in computer science.
Saying “there is some way to use P to efficiently accomplish X” isn’t necessarily helpful to someone who can’t find that way. We want to say: if you can find a way to do X with H, then you can find a way to do it with P. And we need an efficiency requirement for the statement to be meaningful at all.
This is the typical way of talking about “more useful than” in computer science.
Saying “there is some way to use P to efficiently accomplish X” isn’t necessarily helpful to someone who can’t find that way. We want to say: if you can find a way to do X with H, then you can find a way to do it with P. And we need an efficiency requirement for the statement to be meaningful at all.