Think he big difference is power fc gives you the ease of adjusting without having to plug an computer in, which can be handy. Also allows for monitoring of systems, AFM, injectors, knock, revs, speed, boost blah blah.
Another big plus with the power fc is that it is fully portable and can be resold alot easier than a chipped ecu.
Bottom line, is it worth it? Perhaps that is something that only the person fitting the power fc, or remapping their ecu can answer, but remapping is definately a good cost effective way of squeezing more out of your car.
If you have a chip already, makes remapping even more cost effective.