Only if you're talking about other people's clocks and not your own. Your own clock is one second per second, but someone else's may be slower or faster relative.
So then you say take someone else's clock and compare it to your own clock, but that is still just a pure number. A speed is not a number, it has units like meters per second. A ratio of two clocks has no units at all, the units cancel. Whatever number you get, 3 or 9, it's just a factor by which two clocks disagree. You can absolutely interpret this ratio as a rate, but that doesn't make it a speed.
And a speed is exactly what the slogan needs, because the diagram/geometry it's using involves a right angled triangle where on one side of the triangle is your speed through space, and on the other side of the triangle is your speed through time, and the hypotenuse of the triangle is fixed at c (since every object travels through spacetime at this fixed speed).
For that to mean anything both sides have to be the same kind of quantity. You can't put meters per second on one side and a bare number on the other and call it a triangle. Nor can you patch it by multiplying the ratio by c to give it units, because the thing you get then grows as you speed up instead of shrinking. Either it has the right units and the wrong behavior, or the right behavior and no units at all. There's no version of this geometry that produces a consistent picture.
You can say the age of the universe is 14 billion years, but that's in our reference frame.
In another reference frame it may be a different number.