The computation model is the underlying code that makes glide work. Basically the original computation model is what Apps currently run on and is hard to maintain and not necessarily efficient code. When Glide added pages, they rewrote the underlying code from the ground up, so currently Pages uses the new computation model. They are now working to convert Apps to that new updated code.
From our standpoint, it really shouldn’t mean much to us, other than some things will most likely run more efficiently and faster. I’m guessing it will also open up the possibility to have similar components that can be used between apps and pages, and it will allow more of the glide staff to more easily maintain the code and add new features.
It’s really just a new updated version of the underlying core code that makes glide function. In other words, it’s not really meant to be a concern to the end user and they largely shouldn’t know the difference.