An interesting experiment, but even as the author states "it's a fun experiment". It makes things easier to read & understand for beginners, maybe, but he even states that it's not for beginners. If I have to be a C power user to use it, I imagine I'd feel more comfortable without it. Just my opinion though.
I think quite similar about this, its in some way like training wheels on a motorcycle.
But I think there could be quite interesting uses for Cello, namely you do your prototyping with it and then you trow out the library and refactor the code to pure C.
