Most professionals seem to use email plenty. In some cases, it's the only way to get to people.
In a entry posted here a few days ago,
If I had needed an answer or clarification of what I heard them say, I would have been quite comfortable using email.
I use email frequently to track people down and to start conversations. If I have a detailed, complicated question, I know my sources appreciate getting the questions succinctly (I hope) in writing before we talk on the phone.
And if we don't talk on the phone and they respond by email, they know that whatever material I use, they have a written record of.
My advice to writers is let common sense prevail. If you ask a question via email and the answer seem odd or untrue, verify it somewhere else. That's just good standard journalism practice no matter where you got information from.
But don't be shy about using your keyboard as a tool for gathering information. Editors 100 years ago told reporters not to trust a new technology that was becoming widely available then: the telephone.