I'll stick with what I've been saying for years: slow RAM is better than no RAM.
I have to agree with you on this one, because having ANY fast ram - even if it's of the slow type will open up more possibilities of what can be done on the Amiga.
But I don't think the point of using GFX card ram as fast ram is that it actually should replace any
real fast ram, no I think the point is that it simply is meant for adding more to the already existing fast ram. If I understand things correctly, the GFX ram will have a lower priority than real fast ram, which means that it will only be used when it's needed.
In my opinion, it is a GOOD thing Elbox have done here (provided that it actually works that is).