Tiny sink, tiny bathroom. 2" cast iron right there. Any reason not to use rubber T?

[CanOfWorms]

I have a very small powder room that I want to put an even smaller sink into. There is a 2.5" outside diameter cast iron pipe right there running floor to cieling.
My first thought was to cut and put in a pvc drain T using no hubs. But that is 1 foot from the toilet at eye level. It would be unsightly and big.

Is there any reason I cannot use a rubber T like the one pictured below. I know it will also be ugly, but it will be smaller and I could probably get away with painting it white like the pipes.
I also put a little sketch of the corner.



Here is a sketch.