Sometimes it is good to prefer the Photoshop designs when you need to design the similar elements again and again. But it doesn't give the accurate look that an original HTML and CSS gives. It depends on the situation also, if you don't have enough time to design the images or elements, then you may also prefer Photoshop.

In order to make the photoshop designs work in web, the designer usually cuts up the design into images which is painful to implement and dreadfully slow since each image has to load or otherwise you have to implement it using CSS and then it never looks like the original design. Getting coded designs is my preferred way of receiving designs.

Before going in any direction, it starts as a rough sketch for me. Planning my idea and understanding the direction before I crack open an application. That being said, when going the code route it makes since when trying to work out the usability and functionality of the project. Because an actual prototype can show the expected behavior in the environment it's meant to viewed in. It may be a bunch a plain boxes void of any style but it works. However, when it comes to the traditional meaning of the word "design", code falls short. Even using pre-built components required some design app to "skin" it. When determining the look at feel of a project I go from sketches to Photoshop / Sketch before going to code. Mainly because outside of using CSS to style elements, more complex skins need to be established before being applied to the project.

Yes if there are many effects.

Designing by Coding always! Normally what looks good in Photoshop doesn't look good when implemented on the web. Yeah, yeah, it's time consuming. But believe me, the result is always good this way.