Why we use Illustrator and Photoshop rather than Word or Excel to create print data (flyers and posters).

Word and Excel have gone through many versions, and compared with the past they now let you decorate documents with all sorts of shapes and even create flyer-like materials.
You may also occasionally see wording in commercials and ads along the lines of "Data created in Word or Excel can be printed as is."
If you can make it in the Word or Excel you use every day, some people may think there's no need to go out of your way to use new software (Illustrator/Photoshop) just to create the data… however,

there is a fairly clear difference between data created in Word and data created in software like Illustrator.

Let's talk a little about that difference.

The biggest difference is resolution—that is, how smooth the lines look when printed. Word and Excel are fundamentally designed around the paper sizes and printer capabilities typically used in an office. Illustrator, on the other hand, is used to create everything from small card-sized data to giant poster data, so you can specify the resolution when creating your file.

Next, about color. Word and Excel display colors using RGB (the three primary colors of light: red, green, and blue). Printed materials, however, reproduce color by mixing CMYK inks (cyan, magenta, yellow, and black). RGB easily produces bright, vivid colors, but CMYK has difficulty expressing that brightness and vividness. As a result, colors can come out duller in print than the colors you specified in Word. With Illustrator, you can choose between RGB and CMYK when you create the file.

Word is software for writing documents, and Excel is spreadsheet software. Since their basic concept isn't built around graphics, you can get creative within the available assets, but it's difficult to build something from scratch or customize parts of it.

For that reason, the easy-to-use assets end up being reused over and over, and it's not uncommon for the finished product to look rather "run-of-the-mill."

If you're going to advertise or promote your business, dedicated software is essential for creating beautiful designs that set you apart from the rest!