Not really - it's an issue if you are trying to do both head and shoulders portraits and environmental portraiture at the same time, but with a say 16mm extension tube, infinity focus is still going to be somewhere around 30 feet. So unless you're trying to shoot a mountain and your sitter in the same frame and on the very next frame, fill the frame with their face only, it's not likely to be a problem. And the OP's query was about getting closer for portraits, so the infinity vs. macro issue is not really in play here.