Ebooks are delivered almost instantaneously. You can purchase, download and start reading them within minutes, without leaving your chair. You don't have to go to a bookstore to buy them, neither wait for them for days, weeks and sometimes more to arrive in the mail.
No trees are required to manufacture paper for the pages of ebooks.
Ebooks are portable. You can carry a whole library of hundreds of books with you, on CD, in a laptop, notebook or any ebook reader, without worrying about their weight.
Yes. You will not download a computer virus or any other malicious file when you download eBooks or eBook readers. Additionally, Adobe readers have built-in security and encryption features to protect against copyright violations. It is sensible, however, to ensure that your virus protection is always up-to-date.