As far as it being easier to read in running text, I can't see it, but if the designer of a given work truly feels it provides that benefit, then so be it. I just would prefer for this style to not be used on the web, even though it is becoming available along with other advances in web typography. I just think it looks bad and it's hard to read.
But having said that: the kernel of easy- to- agree- with in your comment is, for a lot of the figures that tend to get typeset on web pages, lining figures are the more appropriate choice.
That said, when set in running text and when describing things that are, effectively, proper nouns (IP addresses, street addresses, phone numbers), old-style figures often read better and are more attractive.
You should read up on typography before decrying things about it. Robert Bringhurst’s The Elements of Typographic Style or Warren Chappell’s A Short History of the Printed Word are two great places to start.