Why do people say that under the Chinese rules komi needs to be an odd number?

I really don't get why we couldn't use a 6.5 komi under, or any other even number, for the Chinese rules. I've heard arguments around the fact that the minimal win for White is 0.5 and for Black it's 1.5, but so what? It would just flip the minimal win around, as shown below, it's not like one of the sides cannot win anymore. So, if anyone is able to clarify that argument, I would highly appreciate it.

The other argument I heard was about one of the sides having one or more stones on the board, which I cannot understand either, because there's no such requirement in Go as far as I know. I think people mix this up with AGA's and other rulesets attempts at making Japanese counting coincide with Chinese counting.

Smallest victory for White with a 7.5 komi:

184 vs 177 + 7.5 = 184.5 (W+0.5)

Smallest victory for Black:

185 vs 176 + 7.5 = 183.5 (B+1.5)

But under a 6.5 komi:

184 vs 177 + 6.5 = 183.5 (B+0.5)

183 vs 178 + 6.5 = 184.5 (W+1.5)