If you dont train with them somewhat regularly, they may make you slower. Your position will change, hopefully towards being more aerodynamic.
But this change in position will use your muscles differently, and may affect your ability to breathe as well.
If you have your hands together, but your sitting more upright than normal, becuase your bars are higher, you could be actually increasing your wind resistance compared to riding in the drops, or on the tops.
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"You should already be aware that riding with people who steer with their elbows, stick food to the top tube of their frames and ride around in dick togs is not a great idea." -- Classic1