They're just trying to make a buck like everyone else. Advertisements and commercials are part of the fabric of our society. Just watch out for the one with a virus. Let's first try to understand what a zipped file is and why they exist. Transferring data from computer to computer over the Internet can be a long process, especially if the file is large.
Most files contain large amounts of blank space.
This was especially important for large graphics files like photographs. With this better file transfer ability came the desire to transmit many more files over the Internet. It became cumbersome to compress and then send many files at once, you had to do each one separately. Enter the zip process. Zipping a file certainly means compressing it, but it can also include several files, a whole folder, or even a whole application all zipped into one easy to send file.