Videos do help definitely, yet they do also slow down your website.
I did a small experiment with this, perhaps someone might find it interesting.
Here's a graph of my "video" clicks from google.
The part where it's dead, is the part where I "optimized" videos - they were still on the page, but didn't slow it down. They were also not idexed as a result of that.
Website speed wen way up, but if you compare the video clicks graph with web click graph - you will not see any improvement in clicks based on the improved website speed.
So as a result here, I removed videos and increased website speed - I lost about 200 monthly video clicks and didn't gain any "web" clicks.