Partly the advantage is that you have CSS selectors to examine your document (I don't know if Ruby/Mechanize does that - I'm just saying what is good about node

Partly the advantage is that you have CSS selectors to examine your document (I don't know if Ruby/Mechanize does that - I'm just saying what is good about node+jquery), and you have a language that all web developers know about. So it's about minimising friction from doing front end web work to doing scraping work. At my company this gives us a financial advantage - we can hire basic jQuery web developers to work on our scrapers.