Ask HN: Use Olark or email to convert customers?

I am wondering what is better to use for converting visitors into users. This article below says its better to use olark but doesn't email give you more flexibility and time when trying to convert someone? What experiences did users have with olark vs. email for conversion? http://www.zurb.com/zurbapps/article/526/3-ways-to-keep-customers-engaged-and-happ