I think there is always an assumption that the JS devs will thank you for not making them learn Swift and Java Kotlin, and that time will be saved by doing so.

I think there is always an assumption that the JS devs will thank you for not making them learn Swift and Java Kotlin, and that time will be saved by doing so. In both cases I think the assumption is wrong however. Devs love to learn and this will speed up development overall and produce a better product.