Re: Does landing page really matters in a phone call based campaign?
It's a very generic question. I would say that whether your aim is to drive leads, phone calls or sales, your landing page should convey the realistic message in terms of what ideally users are looking for. For driving the phone calls, the landing page should be responsive so that it serves the audiences using different devices. That's my understanding here.
Once the users are really able to get the information they are looking for, they might take the action in the form of either a phone call if they have some query, filling up the form or completing some transaction.
The content on your landing page should be genuine with ease of navigation, so that users get the right information at the right time.
More details around the landing page can be found here: https://support.google.com/adwords/answer/2404197?hl=en