PDFs are an extremely useful media for presentations because they can include eye-catching fonts and graphics to capture the attention of your audience. In addition, PDFs are very stable, your design is crystallised into a format that will not become distorted and messed up when viewed with different browsers and devices. Your design remains faithfully as you created it.
In terms of file size, PDFs are relatively light weight, as images and fonts are compressed, so they are ideal for sending by email or, even better, uploading to a file-sharing site like Dropbox. Why use a file sharing site? Firstly, with file-sharing sites you only need to send people a link, shortened using a site like Bitly, not the actual PDF, so their inbox does not get cluttered with files. Secondly, you can upload a new version to the site and your client will see the updated version the next time they click the link.
People are often surprised that you can create a navigation structure in a PDF so that it behaves just like a website, you tap the navigation button and jump to the relevant page, rather than scrolling through the PDF page by page.
To prepare such a PDF, you can use Powerpoint as a graphics engine to build a multi-page presentation with an attractive looking navigation and insert hyperlinks to jump straight to the different pages. When go to the next page, you can create a secondary navigation there, so clicking a primary navigation opens up the page with a secondary navigation.
When you save the presentation as a PDF, all the website-style functionality remains intact, and your client can enjoy a presentation with all the advantages of the PDF format, plus the additional benefit that it behaves just like a website.