"Continents are categorised as such for convenience."

Indeed. One might as well call Romania a continent, which, were that definition foisted on the West over generations globally, would be convenient for Romanian dictators.

"It may be arbitrary, but human society can not function..."

My point is that it's not arbitrary. It's precisely to elevate Europe to some supposed natural geographical separation from the metaphorical 'other' that this specific definition is undertaken. Arbitrary would be that lackadaisacal miscategorization without cause or reason. India, Greenland, land on either side of various conceivable separators would have been so defined as has been Europe were this arbitrary.

It's not arbitrary at all.

You go be well mastered as you will. As for me, I will continue to anticipate and advocate for increasing the ability of free sovereign people to secure themselves, their possessions and communities against rapine overlords seeking only power. Society is far more beneficial to all concerned with the individuals comprising it secure from violent force. This security increases every day, and we see that people are increasingly subjected to violent oppression globally, and that ability of technological advance strongly facilitates their resistance to coercive force as time goes on.

I point out that once sovereign free people effect their security from coercion, they need neither to obey, nor command. They then become able to voluntarily effect society, and this continues to burgeon daily. Wallow in your master's shadows as you will. Some people like that kind of thing.