[Coco] Any reason to put a 6309 in a Coco2?

[John Guin]

 Hello all,

My wife got me a 6309 for Christmas, and I am itching to install it.
However, I can't think of a reason to put it in a Coco2, which is all I have
available at the moment.

So can anyone think of a reason to install it in a Coco2?

And a related question:  was the Coco3 100% Coco2 compatible?  Was there
anything (at all) a Coco 1 or 2 could do which a Coco3 could not?  It seems
to me if the answer to this question is no, there is nothing a Coco2 can do
which a Coco3 can not, then there is no reason to install the chip in a
Coco2.

Thanks,
John Guin