What is a nofollow link?
No follow links can be used to link to a webpage that you don’t want to transfer your PageRank (page authority) to. The link to the target page will still be there but you are telling no to “nofollow” that link when crawling your website.
If Google do not follow these links, is there any SEO benefit?
Googles stance on Nofollow links is a little vague – “In general, we don’t follow them. This means that Google does not transfer PageRank or anchor text across these links.“
‘In general’ can mean a number of things and all SEO’s have their own opinions on this. So even if they don’t have a direct impact on SEO, they do benefit indirectly by diversifying your link profile.