And why is this a good thing?
Tell me what is fundamentally wrong with screenshotting an interface, playing with it a bit, coming up with something you like then turning it into code?
Every approach is unique to its designer, and it's situation. But I have yet to (personally) find Photoshop (or a hybrid approach) more effective and time-saving when you deal with a large project. Artboards are MUCH easier to keep track of and group, and with something like Mirror [1] you will save hours in exporting/slicing/sharing over the course of a project.
Photoshop was not made for UI design. It can do it, but it will rarely be the best tool because Adobe is not catering features for that niche.
Adobe actually has a tool for this. http://html.adobe.com/edge/inspect/
I'll go against the grain here and say that 80% of the UI design that I do is based in the browser.
Certainly getting a style and architecture down is helpful before hand but the design really doesn't come to life until I get into code. Some might say that this isn't sustainable on a large project but I'd argue that using HTML/CSS and github as a tool is just as, if not more, useful than photoshop/sketch/whatever.
Do you have any good resources to learn more about how to develop with Sketch?
[1] http://bohemiancoding.com/sketch/help/ [2] http://bohemiancoding.com/sketch/community/