I am maintaining an Anglaur app just now. What a waste of effort. Everything would have been so much simpler if it was kept server side. Instead we have a ton of duplicated logic.
Stating the obvious, but that's the fault of whoever decided to do it in Angular and didn't understand the trade-offs of single page apps. If an app can be just as easily (or more easily) implemented server-side with no 'relevant' impact on UX, it probably should be.
It does give a bit more interactivity, but had it been up to me the majority of the logic would be server side with a bit of client side JavaScript. The amount of duplicated code for a very small amount of extra interactivity really doesn't seem worth the effort to me.