>is there really any compelling reason not to choose Kotlin over Java?

Kotlin is being developed primarily by developers based in Russia. Putin relies on geopolitical conflict for consent manufacturing within the country. One of his future antics could turn into a real crisis, where Russia ends up sanctioned and isolated as a result, after a series of tit-for-tat moves, with the corresponding disruption to normal business processes.

Being a Russian product it also carries a risk of one day receiving an update with a payload from Russian secret services, if they find your firm sufficiently interesting. But it's a general consideration with software/hardware from "adversary" countries like China or Russia. The story with Huawei is the same.