If the step 1 allows you to get your product out more quickly and that has enough business value, I don't see why not

That's fair and there is definitely a use case for these frameworks in order to quickly ship a product on several platforms.

There is also an inherent cost to rewriting all your codebase at once that should not be under estimated.

For something so big and integrated as messaging, I am not sure that this was a good match.

Admittedly turning messaging into a do all à la WeChat was very probably part of the initial plan.