The main advantages to rendering to frames then compiling later, if there's a screw up, you don't need to render the whole thing again, (eg you forgot to make character A turn to the left 30 seconds in), you can start / stop rendering from any point in the sequence, (so if poser crashes, power goes out, you just want to check a few frames in the middle of the animation, etc), you can control codec options more easily, (compression, bit rate, etc),  choose codecs not supported by Poser, (Divx, QT, FLV, Mpeg, etc etc)...

plus, rendering to frames means you can do many tricks like overlaying an animation over other footage by rendering the animation to PNG or TGA that support alpha channels.... the list goes on.

Airport security is a burden we must all shoulder. Do your part, and please grope yourself in advance.