Many reasons: Chainspell-Warp, Invincible/Perfect Dodge then RUN, Manafont - Warp/escape...o_O just a few on my head.

This doesnt help Astral Flow i dont see how it does..all it does is make it so you cant use it once you zone. Same for SAM 2Hr, or WAR 2hr, or anything that lasts.... you lose its effect. Slight nerf i think.

Benediction is obviously an instant use, and once used theres no duration.