I think the idea is that the size of the grants remains roughly the same (or, you know, it's 1/4 of the size but lasts only 1 year). You're right that if they increased it, you could see that as just doing a bit of a risk trade-off. But my impression is that they aren't? And so it's just a comp decrease (albeit a more minor one the more stable the company's stock is).

Of all things in the equity world this certainly doesn't seem especially evil, but what I can't stand is the half-hearted framings of this as good for employees. If you're deciding you want to keep more equity for yourselves, fucking say so.