why do foreigners invest in this if they can't actually gain ownership in the alibaba company itself?

It goes for all Chinese companies, I believe. Want Chinese exposure? Deal with it.

Diversity of a portfolio; as S3th said. China, as much as I don't want to admit it, is poised to potentially surpass the US market in the next decade. If I can have a tiny fraction of that pie with little risk, why not?

Same reason you invest in anything else. Because you can sell it for more later

Its same shit, u just dont have voting rights

Money

It depends on whether the company offers voting rights with its shares. It's common for companies to have A and B class shares with different voting rights, so I wouldn't place much importance on it unless you're a billionaire and want a sizeable piece

Auditing practices in Chinese companies is shocking so I wouldn't touch it with a bargepole outside of the 5% global index allocation