The typeface you use in your slides matters. It talks about you and your business.
Myriad Pro is great. Yes, it is so good that it made it into the back of every single iPod, iPhone or iPad. But when you produce Illustrator work and use Myriad Pro, it does not talk good about you. It is the default font.
The same way, Calibri is a good typeface, but when you use it in an A4/Letter-sized document it shows up you did not spend even a minute thinking on what font to use for your document. You did not take a choice.
Even though ordinary people do not pay attention to design, and usually focus on content, there is people who cares about design that will be able to tell what kind of person you are, just by looking into the typeface, the layout and the elements present in your design work.
I always remember the following sentence by Jessica Hische, that says:
I’m a believer that if you have a favorite font, you’re probably using it inappropriately or way too often. — Jessica Hische on Thinking Thoughts.
Each typeface has its limits and its own voice.
The same way this happens with fonts in computer software, it occurs in other aspects of design. Before you ship something, think about what your design is saying about you.