My boss is the queen of doing this. I don't know how many times she has composed an email to someone in the admin office, sent it, and then immediately walked over (different but nearby building) to pop up at their desk and ask about it. Generally not things that are time sensitive, either, just things that are IMPORTANT in her mind.
She does it to me, too. My desk is right outside her office. She will come out and say, "I just sent you an email..." (literally hit send right before getting up) and then she'll sit down and want to discuss the topic, without even giving me a chance to read the email. Sometimes she will send me the email, then immediately print it out, bring me the paper copy, and want to start talking about it without giving me a chance to read either the electronic or paper version.
With me and the admin office, she also likes to just pop in with something she wants taken care of/looked up right now
, without considering that maybe the person was in the middle of doing something else. With me, as her direct employee, I can kind of understand it--my time is her time, I suppose--but I think the admin staff get rather tired of it.
I think part of the irritation with the email + visit is because, with words/body language/tone/etc., she really gives the impression that she thinks you won't do what she wants in a timely fashion with just the email. Like you are so eager to get out of work that you will pretend you never got the email or ignore it or deliberately misunderstand it if she doesn't immediately show that she's watching you. For some reason, this kind of grates on people.
I think what the OP describes is fine, though. If you can articulate a reason why both the email and the call/visit are necessary, without impugning the character of the recipient (unless of course you have hard evidence of bad behavior), it's probably reasonable.