I agree with the above in that it's not good for more urgent help - also, there isn't the immediate opportunity to ask them to elaborate or about anything they haven't answered. It's easy enough to miss things in emails. The thing about phone calls is that sometimes it can lead you down a different path with may prove more beneficial more quickly.

If you're happy to wait around and accept that through either phone or email they can't really advise you of anything - only listen and potentially help you reframe the issue, then go for it.