Yeah, it is inconsistent that he is either a spirit or a physical being.
Just so people won't be confused, he kinda is a physical being, to Sonic as they are connected. For others however he is invisible as they don't know who he is. Take the movie rise of the guardians, in that movie, some characters are physical beings and can be seen by children while some characters can't be seen and therefore become like a spirit. That is how I view Sonic and Chaos. Only Sonic is able to see him and therefore Chaos is a physical being for him and only him.
Yeah, it is inconsistent that he is either a spirit or a physical being. Just so people won't be co
