Hey, this is a good idea, I'll add a Feature request tick to out product board and also leave this thread as an open feature request.
We're still in the very first stages of seeing Slicemachine come to life, so modifications are moving around very quickly. That's why it's constantly changing!
In the meantime, even if there's no copy button you can still create as many similar fields as you need!
It's cool that your are bringing this up, because we are actually working on a feature just like this except it's one step further so will help you improve your productivity even more.
The idea is that we will provide a copy button and a full suggested code snippet depending on the framework of your project. For example for above in a Nuxt project you would see: