Photoshop is just a tool. There’s no rules as to which way you should be using it.
Is Photoshop productive for web design?
It depends. How are you using it? Are you happy with the workflow? What else have you tried? There’s so many habitual, personal things that get molded when using any tool. It’s very subjective. What works for me might not make any sense to how you do things.
Are you working alone? With developer? Have clients? All of these things might at any point in time make you switch between multitude of tools that you have at your disposal.
For me, I use Photoshop to get some creative ideas polished, but I always start with low fidelity pencil and paper sketch. It’s much faster to iterate on paper, throw ideas together then later produce higher fidelity comps for client or whomever.
How you present those ideas to clients is in-itself huge complex process. Some designers elect to do big reveals, where they present a client nicely polished design after spending lots of time working on comps. Some deliver lower quality prototype that they iterate on as they work. Most of that work is done in browser, and in my opinion more realistic representation of your design. It’s a living thing, not a Photoshop comp that client is looking at on a projector. There are pros/cons to both approaches.
You need to figure out how your process will be structured and how Photoshop fits into your workflow.
Hope that helps,
Here’s a great listen: ‘Extreme tool anxiety’ with Brad Frost and Stephen Hay