Before Version 1.9 , smooth scrolling effect only works on the same page. Now , you can smooth scroll from one page to another, which will make this plugin useful for setting up site-wide navigation.
Currently, there is a small glitch : When clicking the anchor link the page would flicker. If you mind it, downgrade to old versions https://wordpress.org/plugins/easy-smooth-scroll-links/developers/.
Enjoy the new plugin !
Happy blogging !