I don’t understand how (or why) managing the reactivity of data and having multiple instances are coupled. Also, implementing your own reactivity is very unint

I don’t understand how (or why) managing the reactivity of data and having multiple instances are coupled. Also, implementing your own reactivity is very unintuitive. You need to implement your own “diffing” (is this change worth rendering) to know when to force Vue to render. This is definitely not how Vue was intended to be used.