I like to be given a warning about where I will end up if I click on a banner advert. I find banner adverts distracting. If download speed remains unaffected, I donot mind watching multiple banner adverts. Banner adverts slow web pages when they download and are a hindrance. The purpose of an animation sequence should be obvious.
Web sites using animation to send fast dynamic messages to the public are well focused.
Animation content must cause me to revisit the site. If an animation is captivating I am driven to browse the site. It is easier to remember information seen on an animated site than from a plain text site. My interest in viewing an animation is affected by the length of the animation. I like to be able to interrupt an animation at any point and have full navigational control.