http://www.runitonce.com/poker-training/videos/wcoop-main-event-part-3/

Beginning at 18:00 (for context) to 18:45 he's talking about high equity semi-bluffs (OESDs otf) and concludes with the following:

"The deeper we get the more the blocker effect matters, the shorter we get the more the equity effect matters, that's the basic rule."

Could someone elucidate this for me and explain why it's the case? Thanks for your time.