Thanks for the info SigEp265... im new and curious on this field....
1. Why use Sketch and not Illustrator if one wants to make a mockup? Does Sketch provide extra abilities? And if so what might those be?
2. Will Sketch provide the ability of mobile app design?
Sketch is a one time fee as where adobe illustrator is subscription based.
This article might help :
Learn how to effectively use mockups using the power of nested symbols.
medium.com
I personally have been trying to get away from adobe products. I have been using affinity, designer, affinity photo, coreldraw, pixelmator, and sketch