It is worth it?

You've laid out the hypothetical "what if" here. You do have to consider why, in the first place, you got the wonderful Pen. Your subject matter is what will determine your answer. In my instance, I've got the FL-20 and 2 FL-50Rs for my experiment/practice in flash photography(purchased previously for my DSLRs). I determined that the built-in flashes were not giving me results, indoors and outdoors that were reliable. To be certain, I acknowledge, these flashes are barely used, but my kit is ready and I do practice set-ups to learn techniques.

My initial drive was fueled by some real poor outdoor shots w/ my E-410 and built-in last summer when I shot some dog pics in shadow and bright sun. Flash photography is a different beast for me. I see creative opportunity but I also note a meaningful learning curve. That curve begins with knowing what you want to capture with your camera, be it the E-P2 or my E-3.

Size is one of the main attractions of the m4/3 format. When you consider the flash topic with the E-P1 or 2, you compromise that base. The next compromise is "size matters". The power limits of an FL-14 or FL-20, creates another compromise. So, what is it that you are trying to accomplish with your photography? Is it portability? Is it IQ?

Our EPL-1 was purchased partially for it's ability to work with the FL-50R RC flashes, anticipating my further interest in strobist techniques. I can possibly see the combination of my 20 on an e-P2 working with the 50's (as slave flashes). Good luck absorbing my 2 cents.

 

Sometimes I like flash but not in the normal way.
I like to drag the shutter in good to bright light. The flash adds the sharpness to the subject.

Example.... Exposure calls for 1/125 @ f5.6.
I'll use the flash and shoot at 1/15 @ f5.6
The background blurs and is over exposed. The subject is sharp and exposed close to right on.
I'll adjust the exposure slider in LR to get the background where I want it......

I don't do it much but sometimes. I just bought BB's little flash.
Normally, the Pen does well without flash but it's nice to have for creative uses.