PowerFrameworks advocates the use of number values on the bar, column, and waterfall charts, instead of axis values. This is a kindness to your audience. When it is possible to put a value in the segment, do so. Your audience will not have to line each segment up against the axis to read and understand the message/data. This is the preference, which is supported by the PowerFrameworks templates.
Also, using an axis with segment values is redundant. Remember that it is important to eliminate all redundancies from your slides. If you use an axis, eliminate the values. You'll notice that there are some templates available with axis only and the numbers are not formatted to appear. Sometimes it is strategically important to keep the exact data off the slide.