Yes if and when, and I can't stress this enough, done properly..
They don't have the same power they used to, but then again no one single type of backlink does anymore and it goes through any type of link. .
By done properly, I mean:
most of them (BUT NOT ALL OF THEM) powered up by varying numbers of tiers of backlinks (T2-T6, come with just T2, some with T3, T4 etc) and not done exactly the same way on each one (if you use the same sage on the same tier levels for every single web 2.0 or any identifiable backlink pattern it will be obvious and likely get devalued quietly)
Also, make sure the content of the Web 2.0 is quality accurate and satisfies the search query it would likely rank for. Also, more important than ever before, make sure they are filled out completely with some sort of NAP information etc.
The more content you can get on your Web 2.0 properties be more excuse they will end up getting as well, back in the day it used to be you could throw up a one page with 2.0 with 300 words of okay text and minimal if any contact information or any other pages that are typically recommended and call it good, nowadays that won't even get indexed like that, you're much better serve to have minimum of five articles per each fully configured Web 2.0 property roughly 1,000 to 1500 words per article, and that's a minimum of five.
Nowadays is more about quality than quantity, so yes they still work, but blasting a bunch of gibberish articles on one pager GSA or Scrapebox web 2.0 and pointing it at your money site just isn't going to cut it anymore