pt2. As soon as you start having complex UI logic in place (eg: an animated chatbot, or an interactive tutorial) the last thing you want is to mix it up with business logic, network or db calls and what not. Not to mention that in more and more fields of app development (health, finance, banking, etc) testing is an obligatory and regulated component you cannot avoid even if you think it is bad practice (??). Each project has it's own requirements and therefore architecture.

@NiteOwl, this is really not true, apple itself has begun integrating VM in some example projects or documentation, not to mention that all of the example that the poster keeps spamming on all possible Apple forums and channels are extremely trivial. I tend to not trust who speech with so much confidence, but just look at the project he claims he improved, it is definitely a terrible one to begin with, easy to improve it in any way.