The instant gratification they provide in being able to buy a book whenever you like. Instant gratification isn’t without its perils. As a result of such an urge, I have a long list of books on my iPad that I just haven’t the time to read. They’re now paid for and mine only. If they were physical, impulsive purchases I could at least give away, sell, trade or return them. Instead, I’ve spent my $9.99US and must live with the fact.