There are no choices to be made. Both websites will exist side by side just like any other website on the Internet. PokkenClub will grow with Pokecharms, not replace it. It's not as if by joining one website you delete your membership with another after all.
Given that I am pretty solely responsible for PokkenClub at the moment, while Linkachu and Teapot have been, and will continue to be, managing Pokecharms fully without anything more than general oversight by myself, there's definitely no risk of PokkenClub drawing attention away from here in terms of staff.
Really, the goal is the complete opposite of your doomsaying. With any luck, if PokkenClub is popular with a new audience it will help to grow Pokecharms by association. And the software development for PokkenClub, which should give it some very exciting new features down the road, is all - in effect -beta testing for an eventual relaunch of Pokecharms.
At any rate, Pokecharms isn't going away either way.
