Well, its usage is different for different's sake in the context of the web, and that's what I meant. I know this style of numeral is old, but I'm saying that its age does not make it good. We also used to substitute "f" for "s" in some scenarios, but we stopped. Let's stop doing this too.
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.
You're getting downvoted a little unfairly. I disagree with you that old-style figs are like long S's. I strongly disagree that we're better off not having the option. I'm inclined to believe that people with visceral negative reactions to old-style figs are really just reacting to being conditioned to lining figures.
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.